Question: I’m a touring VJ and need an iPad app that lets me mix music videos live with two decks and a crossfader. The clip library should feel instant—even with hundreds of high‑resolution videos—and show animated previews in a grid that stays buttery smooth when I scroll. During a show, I want real‑time effects like glitch and kaleidoscope that I can control with multi‑touch gestures. My clips, effect presets, and project files should sync across devices via the cloud. Please keep the app’s design clean by separating deck/effects/library state from the UI (MVC is fine).


Question: We need an iPhone app that lets employees redeem corporate gift credits. After signing in, the home screen should show the employee’s current credit balance (from our server) and a curated list of available gifts. Tapping a gift opens a detail view with images, description, and price, plus a Redeem button. When Redeem is tapped, create the order with our backend as a single transaction that deducts the item’s price from the user’s balance. On success, show a confirmation and update the balance; on failure, show an error and leave the balance unchanged. Please build the UI in SwiftUI.


Question: Design an iOS keyboard for technical users (developers, sysadmins) that makes typing code and special symbols fast. The keyboard should show a customizable top strip that smartly surfaces symbols based on context (e.g., brackets when editing code, a pipe when writing command lines). Let users create shortcuts that expand into reusable code snippets and keep these in sync across devices with iCloud. Add trackpad‑like gesture cursor control for precise selection, and include a privacy‑focused clipboard history where items are stored securely. Provide a companion container app for managing layouts, snippets, and themes; build it with SwiftUI and organize the app using an MVC approach.


Question: I’m tired of recipe sites crammed with ads and stories. Please create a Safari extension for iPhone/iPad that, when tapped on a recipe page, detects the recipe and pulls out only the ingredients and step-by-step instructions. Show this in a clean, minimalist popover. Add a Save button that sends the cleaned recipe to my account through our backend API so I can view it later in a companion app across devices. Keep the UI fast and simple, and prefer structured data when available with a sensible fallback.


Question: I want an iPhone app that acts like a personal yoga coach at home. Using the front camera, it should track my pose in real time, compare my joint positions to expert references for each posture, and speak corrections like “straighten your back” or “knee over ankle.” After a flow, I want a per‑pose accuracy summary saved to my account. I prefer Objective‑C with an MVC structure. Use UIKit for browsing/selecting classes, and layer a SwiftUI overlay on the live camera preview for guidance. Any required ML/pose detection libraries can be added via CocoaPods.


Question: I’d like a simple iOS app in Objective-C that lets me turn on a personal VPN with one tap. The main screen should have a large “Connect” button, and I should be able to choose a server by country from a list (e.g., US, UK, Germany). Please store my login securely (use the Keychain) and use the system’s VPN capabilities to start the tunnel. While connected, show a clear status (“Connected/Disconnected”) and the IP address assigned by the VPN server. Provide the overall app structure and sample code for the UI, credential handling, and the VPN setup.


Question: Safari on my phone often feels slow and cluttered with ads and trackers. I want an iOS app with a Safari extension that makes browsing cleaner and faster. In the app, users should be able to subscribe to popular online filter lists, manage their own blocking rules, and whitelist favorite sites. The extension must apply these rules to network requests efficiently with minimal performance overhead.


Question: Pop-ups and trackers are making Safari on my iPhone/iPad frustrating. Please build an iOS app with a companion Safari content blocker that stops requests to known ad/tracker domains. I need a simple UIKit settings screen where I can turn blocking on/off and see basic stats about what’s been blocked. The app should also periodically download updated filter lists from our server and apply them so protection stays current.


Question: I travel a lot and want a vault app on my iPhone to keep digital copies of my passport, visas, and ID cards. It needs to be fully offline—no cloud sync or external servers. I should be able to add documents by taking a photo or by selecting a file (like a PDF or image). Everything saved must be encrypted on the device, and the whole app should be locked behind Face ID or Touch ID before anything is accessible.


Question: Design an iOS search and discovery experience that helps people quickly surface older stories and niche topics. Users should be able to narrow results with facets—date range, author, category, and media type (article, video, podcast). While typing, show real-time suggestions coming from the backend, and make them feel instant. The results page should blend different content types in one feed and scroll infinitely, smoothly fetching the next pages without stutter. We'll build this with Objective-C and UIKit in an MVC structure; optimize networking (debounce, cancel, pagination) and fast list rendering.


Question:
Our community wants a place for live, drop‑in conversations. Build “Live Audio Spaces” on iOS where people can join a room to listen, raise a hand to request speaking, and be invited to the stage. Hosts should be able to invite/mute/move speakers back to the audience, and stage participants should have animated avatars. The experience needs to feel real‑time and remain stable with hundreds of listeners.

On the client, implement the room UI in Objective‑C using MVC, use CocoaPods for networking/audio dependencies, and use SwiftUI for the animated avatars on stage. Assume the server owns room state, user roles, and stream routing—define the client contracts and flows (join/leave, hand‑raise queue, host actions, error/reconnect) and make the audio path low‑latency.


Question: Browsing on phones can be hard for people with reading difficulties. I need an iPhone/iPad Safari extension that turns any webpage into a clean, distraction‑free reader and lets me customize how text looks: dyslexia‑friendly fonts, adjustable line/letter/paragraph spacing, and high‑contrast color themes. It should also read the content aloud and highlight each word in sync as it’s spoken, with a toolbar toggle to start/stop. Preferences should sync via iCloud so I set them once and they follow me across devices. Tech notes: ship as an iOS Safari extension packaged in an app; codebase in Objective‑C with a SwiftUI settings screen, organized using MVC. The extension should parse pages in real time and work across a wide range of sites.


Question: Fixed-income investors lack a good mobile tool for building and analyzing bond portfolios. We want an iOS app that lets users browse a large catalog of corporate and government bonds (data from our central warehouse), search and filter instantly by yield, duration, rating, maturity, issuer, currency, and more, and construct portfolios. As users add or remove bonds, the app should immediately show portfolio-level metrics: weighted-average yield to maturity, duration, and a breakdown of credit quality. Include a cash-flow calendar that visualizes upcoming coupon payments. The results list must feel instant even with thousands of rows and a dozen+ filters/sorts, so the list implementation needs to be highly efficient. Use an MVP architecture and integrate our existing Objective-C calculation modules.


Question: Build a Safari extension for iPhone and iPad that helps students as they write on any website. As the user types in a text field or editor, subtly underline possible grammar or style issues in real time. When a highlight is tapped, show a small popover with a suggested fix and a brief explanation of the rule. The text should be sent to our secure server API for analysis, which returns suggestions. The UI must feel lightweight and blend naturally into Safari without adding clutter.


Question: Create an interactive AR study aid for physical therapy students. The app should let me drop a life‑size 3D musculoskeletal model into my room, walk around it, and tap any muscle to open an info card with key details (name, origin/insertion, function, common injuries). I want short exercise animations that show how muscle groups work together. It must feel realistic and dependable: accurate scale, stable tracking, and believable lighting, all running smoothly. Everything has to work offline—bundle the 3D models and anatomy data in the app. Use SwiftUI for the on‑screen information overlays, and you may add lightweight helper libraries via CocoaPods if needed.


Question: Build a custom keyboard for iPhone and iPad that expands short shortcuts into full phrases or code snippets. Include a companion app where I can create, edit, and organize snippets into categories or tags. All snippets should stay in sync across my devices via iCloud so changes on one device show up on the others. The keyboard should be fast, work in most apps, and be privacy-conscious (e.g., only request Full Access if needed).


Question: Design an iOS app that helps hardware engineers quickly browse a catalog of 100,000+ electronic components. Users should be able to stack filters—like capacitance range, tolerance, and voltage rating—and see results update immediately while the list stays buttery-smooth to scroll. Provide a clean, flexible filter panel with easy presets and a quick reset. Signed-in users can save and reuse named filter sets that sync to their account across devices. Build the UI in SwiftUI.


Question: Many of our readers commute with spotty connectivity, so we need a real offline reading experience. Let users pick topics or specific publications to keep offline. When they choose “Download for offline,” the app should fetch complete article content plus inline images and lightweight video previews so stories open instantly with no connection. While offline, users can read, bookmark, and write comments, and their scroll position should be remembered per article. When the device reconnects, the app should quietly sync reading progress, bookmarks, and any offline comments, resolving conflicts in a predictable way (e.g., clear last-write-wins or per-field merge rules). Build this in Objective-C with UIKit using an MVC structure, and outline how storage, prefetching, background downloads, and sync will work reliably on intermittent networks.


Question: I spend most of my day in chat and notes apps and need quick finance math without switching screens. Please build an iOS custom keyboard extension that works like a numpad and adds one‑tap shortcuts for common finance formulas: percentage change, profit margin, and simple compound interest. I should be able to enter values, see a small on‑keyboard preview of the result, and tap Insert to paste the result into the current text field of whatever app I’m using (e.g., messaging or notes). Support decimals and negatives, backspace/clear, basic rounding and percent/currency formatting. Keep it offline (no Full Access), handle cases where third‑party keyboards are disallowed gracefully, and make sure it looks good in light/dark mode on both iPhone and iPad.


Question: We’re building an iOS non‑custodial crypto wallet for power users. The app should generate and store private keys securely on‑device using Secure Enclave, let users switch between Ethereum, Polygon, and Solana, and show accurate token balances fetched from each network. The core experience is an Earn tab where people can browse staking pools and liquidity farming opportunities, see live APYs, and start staking from simple, trustworthy flows. Transactions must be constructed, signed on the device, and broadcast to the correct smart contracts. A clear transaction history should decode data into human‑readable details. Use MVP for presentation and manage blockchain dependencies with Swift Package Manager.


Question: We run a small delivery service and need an iOS app that automatically plans the most efficient multi-stop route using live traffic. Drivers should see an ordered, fast-scrolling list of stops where they can quickly mark progress (arrived, delivered, skipped). When the route is re-optimized or dispatch inserts a new priority stop, the list must refresh instantly and keep the UI responsive. Stops come from our backend, and the app should be able to replan in real time as conditions change. Please build this with a SwiftUI interface and keep a clear MVC separation of concerns. Prioritize smooth performance and low-latency updates.


Question: Enterprise customers frequently reorder the same supplies and want a faster way to repeat large purchases. Build an Order History screen that loads quickly and scrolls smoothly even with thousands of past transactions. Each order should be expandable to preview its items. From any past order, let users either add the entire order to the current cart with one action or choose specific items to add. The cart must comfortably handle hundreds of line items with fast quantity editing and immediate feedback. Data comes from our central procurement API. Use MVVM, keep the main screen in UIKit, and embed a SwiftUI cart view inside it. Prioritize snappy performance and a frictionless reordering flow.


Question: I need a custom iPhone keyboard that acts like a writing assistant: it should suggest context‑aware sentence completions and offer one‑tap rewrites (more formal or more concise). It also needs a clipboard history with fast search and a code‑snippet drawer to save and quickly insert frequently used blocks. All intelligence must run fully on‑device for privacy and offline use—no network calls. Build it as a keyboard extension in Swift/SwiftUI organized with MVC; if third‑party components are needed, use CocoaPods. Please provide the overall architecture and the key implementation details (model loading/inference inside the extension, UI flow, data storage, and snippet insertion).


Question: Build a Safari extension for iPhone/iPad that creates a calm, private reading experience. It should block ads and trackers with rule lists that can be updated from our server, provide an on-demand Reader view that extracts the main article and renders it in a clean, customizable layout (fonts, themes, spacing), and translate text in place via a remote service without reloading the page. Keep everything fast and lightweight so there’s no visible lag, and include per-site controls with an easy way to turn features on or off.


Question: We want a smooth import/export experience in our CRM so large datasets don’t tie up the app. Customers will upload big CSVs (thousands of contacts). The API should accept the upload quickly, return a tracking ID, and hand off the work to a background job. A worker service will validate and transform rows, then bulk upsert them into PostgreSQL under the correct tenant. Exports of large lists should follow the same pattern (background job or streaming) and shouldn’t affect overall performance. We also need endpoints to check job progress and results (queued, running, completed, failed), with basic per-row error reporting. Prefer a queue-based design to decouple the request from processing.


Question: We’re rolling out tiered pricing with per-tenant API quotas (e.g., Free: 100 requests/hour, Pro: 5,000/hour) and need a single, low-overhead rate-limit layer across all authenticated endpoints in our Flask services. Please implement a before_request middleware that identifies the caller’s tenant and plan, enforces the correct limit with minimal latency, and returns the right headers. Store real-time counters in Redis using a sliding window (atomic INCR + EXPIRE on keys like rate_limit:<tenant_id>:<timestamp_bucket>) rather than MySQL. On success, include X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset. If the limit is exceeded, immediately return 429 with a JSON error and a Retry-After header. For billing, add a periodic job that rolls up the Redis counts into hourly/daily totals in the api_usage_logs table in MySQL. The goal is platform stability and monetization, so please keep per-request overhead as small as possible.


Question:
Users need to see who changed a document, when it happened, and quickly roll back to prior work without losing the audit trail. Compliance teams also require a trustworthy, immutable record for investigations. Please design and implement a version history feature for our document service that balances space efficiency and fast retrieval.

Requirements:
- Every significant change (content, title, permission updates) must create an immutable version entry with author, timestamp, and a short human-readable summary.
- Store deltas (diff/patch) instead of full copies to save space, but ensure we can efficiently reconstruct any historical version when requested.
- Keep the main update path responsive by publishing an audit message to RabbitMQ after a successful write; a separate consumer should persist the version record in MongoDB.
- Provide JWT-protected APIs:
  - GET /v1/docs/{documentId}/history: paginated list of versions (authorId, timestamp, summary).
  - GET /v1/docs/{documentId}/versions/{versionId}: return the full content for a specific historical version.
  - POST /v1/docs/{documentId}/restore: restore a document to a previous version by appending a new version derived from the selected one (do not overwrite history).
- Return 404 Not Found if the document or version doesn’t exist.

We’re on ASP.NET Core and MongoDB. Propose a MongoDB storage and indexing approach that is space-efficient yet performant for history queries and reconstruction. Please also define the diff format, outline measures for immutability and idempotency, and ensure the user-facing API remains fast.


Question: We’re onboarding partner laboratories that need to drop off bulk test results and get a clear import report. Labs will upload a CSV or JSON containing many patients to a secure endpoint; the system should accept the file, kick off an asynchronous import job, validate each row, match it to the correct patient, update the EMR, and continue even when some rows are invalid. The uploader should receive a jobId immediately and be able to poll a status endpoint showing progress and counts of outcomes (e.g., SUCCESS, INVALID_VALUE, PATIENT_NOT_FOUND). Build this in Spring Boot, protect the API with a lab-specific API key/secret, and process files via a background worker triggered by a RabbitMQ message (jobId + file location). Expose POST /v1/lab-results/uploads for the upload and GET /v1/lab-results/uploads/{jobId} for status. Prioritize fault tolerance and horizontal scalability so uploads don’t block and partial failures are reported cleanly.


Question: Clinicians need a fast way to update EMRs, and compliance requires that every change is traceable and immutable. Build a backend service that accepts small JSON Patch edits, acknowledges the request with 202 quickly, and processes the changes asynchronously so the app stays responsive. The system must keep a version timeline per record and a detailed audit trail showing who changed what and when. Provide PATCH /v1/emr/{recordId} for partial updates (JWT; return 400 for invalid patches, 404 if the record is missing, and 423 when a concurrent edit is in progress), GET /v1/emr/{recordId}/history for version metadata (JWT), and GET /v1/emr/{recordId}/audit for detailed audits (auditor/admin JWT). Use Express.js, MongoDB, JWT, and RabbitMQ. Describe your data models, queue message format, approach to concurrent edits and locking, idempotency/DLQ handling, and the safeguards that keep audit logs tamper‑evident while maintaining a responsive experience at scale.


Question: We want merge request authors to see a real-time, in-app alert the moment someone comments on their work—no refreshing the page. Build the backend that supports this experience. Signed-in users should stay connected to a notifications stream and be identified with a JWT (map each connection to its userId). When a comment is submitted, store it in PostgreSQL and immediately notify the merge request author over that live connection. Send an event named new_comment with { mergeRequestId, commentId, authorName, excerpt }. Provide a simple comments API: POST /v1/merge-requests/:mrId/comments (Bearer JWT) with { text }, responding 201 with the created comment. Use Express (Node.js) and WebSocket.


Question: Build an automated pricing service for unsold hotel rooms near check-in. Every hour it should read tonight’s occupancy from MySQL, apply configurable rules (e.g., occupancy < 50% and 8 hours to check-in -> 20% discount), and update the room rate. Provide an admin REST interface (Go/Gin) to create, edit, enable/disable, and audit these rules, with guardrails to prevent over-discounting. The goal is a reliable scheduler-driven process with idempotent price updates and clear logs showing which rule changed which price.


Question:
We’re shipping a “profile views” counter so creators can see how much attention their profiles get. Build a backend endpoint that records a view instantly without hammering our primary database, and persist the totals asynchronously. We’re fine with a small delay (a few minutes) as long as the write path stays fast during spikes.

API
- Method: POST
- Path: /v1/users/{userId}/view
- Auth: JWT bearer to identify the viewer
- Body: none
- Success: 202 Accepted
- Errors: 404 if the profile doesn’t exist; 429 when the viewer is rate limited

Implementation direction
- Buffer increments in memory (e.g., Redis atomic counter like profile_views:{userId}) so the endpoint can return quickly.
- A scheduled job periodically aggregates these counters into Postgres (users.view_count) and clears the buffered values.

Please deliver the service (Node/Express is fine), the background job that drains counters, and a brief plan for key naming, batching, abuse controls, and failure handling.


Question:
We’re turning the platform into a true multi-tenant SaaS and need a backend foundation that guarantees strict tenant isolation and fair resource usage. Requirements:
1) Data isolation: All data access through our Django app must be automatically scoped to the authenticated tenant extracted from the OAuth2 JWT. Implement a global mechanism so ORM queries are transparently filtered by tenant_id, preventing any cross-tenant leakage.
2) Governance and throttling: Add a Django middleware that evaluates incoming requests, estimates query cost, and enforces plan-based limits (e.g., max concurrent queries and max query runtime). When a tenant exceeds limits, return 429 Too Many Requests (include Retry-After). Track per-tenant consumption in near real time and surface metrics quickly, leveraging a metrics store such as Elasticsearch.
This is an internal platform capability focused on correctness, safety, and observability rather than UI.


Question: Clinicians are waiting 30+ seconds for patient history searches in our EMR, which disrupts care. We need Google‑like, typo‑tolerant search across diagnoses, medications, clinical notes, and consultation transcripts, with time filters (e.g., last two years). A query like "hypertensione" plus "lisinopril" should return matching patients in under 500 ms. Implement a service that keeps an index in sync with our PostgreSQL data (MeiliSearch) and exposes a simple Express.js API. Every search must be auditable—log clinician ID, query string, and timestamp to our ELK stack.


Question:
Our users need a fast, forgiving search across the knowledge base—process models, analysis reports, and documentation—so they can type imperfect queries, filter by type or author, and see relevant snippets in under a second. The current MongoDB text search isn’t delivering that experience.

Please add a modern search layer with MeiliSearch and connect it to our Django/MongoDB stack. What we’re aiming for:
- Index content from reports, process_models, and documents with fields like title/body/tags/author/created_at; support typo tolerance, facets, sorting, and highlighted snippets.
- Keep the index fresh without slowing requests: do an initial bulk index, then background updates whenever data changes.
- Provide a single REST endpoint for federated search:
  GET /v1/search (JWT)
  q: user query
  filter: "key:value;key2:value2" (e.g., document_type, author_id)
  sort: "created_at:desc"

Return hits with id/type/title/snippet, facet counts, processingTimeMs, and the original query. Respond with 400 for invalid filter syntax and 401 for auth failures.


Question:
We’re launching a personalized homepage and need a backend feature to power a “Recommended for You” section. Each signed‑in user should see products tailored to their on‑site behavior (pages viewed, past purchases, items added to cart). Reads need to be very fast, so please precompute recommendations in a scheduled batch (e.g., nightly) rather than at request time.

Source user activity from PostgreSQL, produce a ranked list of product IDs per active user using a simple approach (co‑purchase or collaborative filtering), and store those IDs in Redis keyed by user_id. When the homepage loads, the API should quickly pull the IDs from Redis and then fetch full product details from Postgres (or a product cache) to build the response.

Expose a GraphQL query: myRecommendations(limit: Int = 10): [Product]. Access must require a user JWT Bearer token. Include sensible fallbacks if a user has little or no history (e.g., popular items), and keep response times snappy.


Question:
Design a fast, reliable permission system that supports role-based rules with per-course granularity, so users never feel lag when the app decides what they can do. Examples: Teaching Assistants can grade only their assigned courses; Course Managers can edit content but not student grades. After OIDC sign-in, load the user’s full permission list from Postgres and cache it in Redis under user:{id} (store as a Set). A lightweight Django middleware should authorize each API request by checking Redis set membership; on a cache miss, fetch from Postgres, rebuild the cache, and proceed. The cache TTL must match the OIDC access token lifetime. When an admin updates roles or permissions, immediately invalidate and refresh the affected user’s cache.

Admin APIs
- POST /v1/admin/users/{userId}/permissions (assign)
- DELETE /v1/admin/users/{userId}/permissions (revoke)
- GET /v1/admin/users/{userId}/permissions (list)
Access control: OIDC bearer token, Admin only.


Question: Build the backend for the BI app’s Custom Report Generator. Analysts will pick dimensions, metrics, and filters from a fixed data model to create ad‑hoc reports. Provide a REST API (Node.js/Express) that accepts a JSON report definition and returns results. The service should safely translate the request into SQL for MySQL using whitelisted fields/joins and parameterized queries, support joins, grouping/aggregations, date ranges, sorting, and pagination, and enforce a per‑request timeout that cancels long‑running queries. For repeated requests with identical parameters, add Redis caching: compute a stable hash from a canonicalized request, check cache first, and cache fresh results with a TTL. Return clear errors when the request references unknown fields or unsupported combinations.


Question: Students should be able to request and download a course completion certificate. After a learner satisfies all completion requirements, show a “Generate Certificate” button. Clicking it should validate eligibility using our MongoDB records, create a certificate job, and start an asynchronous PDF generation via a message queue. The server must reply immediately with a job ID. The PDF uses a standard template with the student’s name, course name, and completion date. Implementation-wise, provide a REST endpoint that writes a job document with status “pending,” enqueues it, and a background worker renders the PDF and updates the job to “completed” with a download URL. Users can check the job status and retrieve the file when it’s ready.


Question: We want an automated dispatch service that assigns the best available rider as soon as an order is marked ready for pickup, so customers wait less and riders stay productive. The selection should weigh where riders are right now, the direction they’re heading, how many orders they already carry, and the restaurant’s location. Decisions need to be fast and reliable. Rider locations arrive continuously. We’ll run this as a Node.js/Express service, keep precise geo data in PostgreSQL with PostGIS, and use Redis Geo to cache each active rider’s latest state so we can quickly pre-filter nearby candidates before a deeper PostGIS check. Location updates are delivered via Kafka.


Question: Recruiters are frustrated with the slow, keyword-only search in our candidate database. They need to quickly find the right people by mixing structured filters (years of experience, location, availability) with free‑text from resumes (skills, projects, certifications). We’re aiming for sub‑second results across 1M+ profiles without hitting our transactional MySQL for search. Please design and build a dedicated search service: maintain a fresh search index via an asynchronous pipeline where profile changes in MySQL publish to RabbitMQ, a Node.js/Express worker enriches and indexes into Elasticsearch, and a separate Express REST API translates recruiter queries into the Elasticsearch DSL and returns relevant, paginated results. Cover create/update/delete flows, relevance tuning, basic typo tolerance, and production‑grade monitoring so we can trust this in daily recruiting.


Question:
We want a simple way for teams to save an existing document or task board as a reusable template, then spin up a fresh copy in any project with a custom name. From a user’s perspective: pick something you’ve already built, save it as a template, and later create a new doc/board from that template with one click. The new item should be independent of the original—content, lists/columns/tasks and nested structure are duplicated, not linked.

Requirements:
- Users can name templates and filter them by type (e.g., document, task_board).
- Instantiating a template creates a brand-new resource with new IDs while preserving relationships.
- All endpoints are protected with JWT.

Implementation notes (Express + PostgreSQL):
- Store templates with name, type, and a JSONB snapshot of the source structure.
- Provide endpoints:
  - POST /v1/templates to create a template from a source { name, sourceResourceId, sourceType }.
  - GET /v1/templates with optional ?type filter.
  - POST /v1/instantiate-template to create a new resource { templateId, name, destinationProjectId }.
- Return 400 for invalid input and 404 when the template doesn’t exist.


Question: Help us reduce the overhead of assigning new tasks. When someone creates a task and leaves it “unassigned,” the system should immediately pick a teammate whose skills match the task’s tags and who has the fewest open tasks. Implement this as a single GraphQL mutation in our Django backend: look up user profiles and skills in MySQL, compute current open-task counts, choose the best match, update the task, and return the task with the assigned user in the same response. Please optimize for fast lookups and include sensible tie-breakers and concurrency safety.


Question:
As we bring multiple fulfillment centers online, we need a central inventory service that keeps counts accurate across warehouses and prevents overselling. Order taking must stay fast: after a customer’s payment, the order system emits an `order.paid` event; the inventory service consumes it, picks the most suitable warehouse based on the shipping address and stock, and reduces the product quantities in a single transaction.

We’ll implement this as an internal Express.js service backed by MySQL and RabbitMQ.

Requirements:
- Warehouses can submit stock adjustments (arrivals, damage) via an internal endpoint; include productId, warehouseId, change (+/-), and a reason. The call returns 202 and is processed asynchronously.
- Every inventory change is captured for audit (who/when/what, before/after).
- If a product’s stock drops below a configured threshold, publish a `stock.low` event.

Core endpoints:
- POST /v1/internal/inventory/adjustments
  Auth: internal API key or mTLS
  Body: { "adjustments": [{ "productId": "string", "warehouseId": "string", "change": "integer" }], "reason": "string" }
  Response: 202 Accepted
- GET /v1/products/{productId}/stock
  Auth: session-based (internal dashboards)
  Response: { "productId": "string", "totalStock": "integer", "stockByWarehouse": [{ "warehouseId": "string", "quantity": "integer" }] }


Question: Make task dependencies behave automatically in our task tool: when a blocking task is completed, any dependent task should switch from “Blocked” to “To Do” and notify its assignee in real time. The experience should feel instant and reliable. Under the hood, use our existing stack (Flask + MySQL + RabbitMQ): the API records status changes and emits a task_status_changed event; a background worker resolves newly unblocked tasks, updates them, and publishes task_unblocked; the notification service listens and pushes alerts via SSE. Please keep the flow decoupled, fault-tolerant, and scalable.


Question:
Students reviewing a classmate’s code should be able to click a line, leave a comment, and see new comments and replies appear instantly for everyone viewing the same submission—no page reload. Please build the backend that powers this real-time experience. When a reviewer opens a submission, they receive the existing comment thread; adding a line comment or replying should immediately broadcast to all viewers of that submission’s page.

We’re using Micronaut (Java) and MongoDB. Each submission acts as its own real-time channel, and the connection must require a bearer token. Provide a WebSocket endpoint at /v1/submissions/{submissionId}/review-comments with these message types:
- Client → Server: ADD_COMMENT { lineNumber, text }, REPLY_TO_COMMENT { parentCommentId, text }
- Server → Clients: NEW_COMMENT and NEW_REPLY containing the full objects (id, lineNumber, author, text, replies)

Design the data model and message flow to be reliable and fast, and ensure permission checks are enforced.


Question:
We’re building an admin-only module in our BI platform so we can safely plug in customers’ databases and pull data for analysis. Admins need to add, view, update, and delete connection records, and quickly run a “test connection” to confirm credentials work before using them. Security is non‑negotiable: host, port, username, and password must be encrypted before we store anything, and sensitive fields should never be exposed in responses.

Deliver a Micronaut REST API backed by PostgreSQL. Core endpoints should cover CRUD for data sources (e.g., POST /v1/datasources, GET /v1/datasources/{id}, DELETE /v1/datasources/{id}, and an Update endpoint such as PUT /v1/datasources/{id}). Provide a dedicated POST /v1/datasources/{id}/test endpoint that opens a short‑lived connection to the target database and returns a simple success/failure result with an error message when applicable, without leaking credentials.

Access is restricted via JWT bearer auth (admin only). Use 422 for invalid configurations and 400 when a test attempt fails. When reading or listing, mask or omit sensitive fields like passwords.


Question: We’re launching a checkout API for our payment gateway and need a fast, reliable flow where merchants receive an immediate “accepted” response (<200ms) even if the bank takes longer. Please design and implement a service that validates requests (schema, HMAC signature, basic rules), returns a 202 with a transactionId and status=PENDING, and pushes the work to a background queue so workers can call the acquirer asynchronously. Provide a webhook where the acquirer posts final outcomes and a polling endpoint for merchants to check status. Persist the final state in MySQL. To prevent double-charging, enforce idempotency for 5 minutes in Redis (e.g., using orderId/transactionId). Core endpoints: POST /v1/payments (HMAC), POST /v1/payments/callbacks/acquirer-x (IP-whitelisted), GET /v1/payments/{transactionId} (JWT). Stack: NestJS with RabbitMQ and Redis.


Question:
We manage thousands of client portfolios and need an automated rebalancing backend that advisors can run quarterly or on demand. For each portfolio, compare current holdings to the client’s target model and produce concrete buy/sell orders to bring allocations back within tolerance while minimizing trading costs and tax impact. Advisors should be able to run a dry run, review the proposed trades, and approve them for execution. The service must provide progress/status for long-running batches and keep a full audit trail.

Operationally, the web API should orchestrate only: a request enqueues one or more jobs and returns immediately; a worker fleet performs the heavy calculations in the background and stores the resulting orders and metrics in the database. Our stack is Python with FastAPI, MySQL for storage, and a RabbitMQ/Celery task queue.

Please deliver the core backend: data model, API endpoints (kickoff, status, results), job orchestration and worker flow (including idempotency and retries), and a portfolio-level rebalancing algorithm that accounts for transaction costs and basic tax considerations.


Question: I want to add rich discussion to our documents: users should be able to start a comment, reply to create threaded conversations, and react with emojis. Please build a new backend gRPC service (NestJS + MySQL) with methods to create a top-level comment, reply to an existing comment, and add/remove an emoji reaction. The data model should capture comment hierarchy efficiently (e.g., via a parent_comment_id approach), and reads should be fast: implement a single call that returns an entire thread with its nested replies, along with aggregated reaction counts per emoji for each comment.


Question: Users should see transfer status changes instantly instead of refreshing. Build a real-time status stream for our P2P payments app: when a user starts a transfer, the app opens a WebSocket and subscribes to that specific transaction. The server should push status updates (e.g., PENDING → COMPLETED/FAILED) from our Postgres source of truth or processing events, and close the connection with a clear code if the transactionId is invalid or the user isn’t authorized. Use Fastify (Node.js) with WebSockets, and secure the upgrade with a JWT. Endpoint example: ws://api.example.com/v1/payments/status. On connect, the client sends {"action":"subscribe","transactionId":"txn_123abc"}; the server pushes messages like {"transactionId":"txn_123abc","status":"COMPLETED","timestamp":"2023-10-27T10:00:00Z"}. Track active connections and message throughput in Prometheus and visualize in Grafana.


Question: Build a partner-facing content API that lets approved companies read public short‑video metadata reliably and fairly. Access must be protected and usage capped per partner so no one can crowd out others. Implement this as REST endpoints on Node.js/Koa, with a middleware that checks an API key plus an HMAC signature on every call. After authentication, apply per‑key rate limiting backed by Redis (token bucket or fixed window using INCR on keys like rate_limit:{api_key}); return 429 Too Many Requests when a partner exceeds its window. Serve the metadata from our primary MySQL database.


Question: We run a multi-tenant process mining SaaS and need a low-latency guardrail to keep the platform fair and stable for every customer. Please design and implement an API usage gate that tracks each tenant’s activity and enforces limits like requests per minute and daily data ingestion, returning clear errors and usage headers when limits are reached. The check should happen in a FastAPI middleware and use a shared Redis for distributed counters with atomic operations. Policies are managed in Postgres but should be cached in Redis for fast reads. Outline the approach (key design, window strategy, cache invalidation, handling policy updates) and ensure no single tenant can overwhelm the app or database.


Question:
We need an admin-facing service to keep tenants within fair usage. Admins should be able to define subscription plans (e.g., Free, Pro, Enterprise) with per-minute API rate limits and resource quotas (like max active projects), and assign tenants to a plan. MySQL is the source of truth; Redis should hold a hot copy of plan settings so our API gateway can enforce limits with sub-millisecond counters (sliding window using atomic INCR/EXPIRE). Build this as an Express.js GraphQL API with:
- Mutation: createOrUpdatePlan(input: PlanInput!): Plan! where PlanInput = { name: String!, rateLimitRpm: Int, maxProjects: Int }
- Mutation: assignTenantToPlan(tenantId: ID!, planId: ID!): Tenant!
- Query: plans: [Plan!]!
Access must be OAuth2 and restricted to system administrators. Include cache warm-up/invalidation on plan changes and a fallback to MySQL if Redis has no entry. The gateway enforcement itself is out of scope; focus on the management API and configuration flow.


Question: Students need a fast, unified profile on their dashboard that summarizes their learning—current enrollments, total time spent, assignment submissions, and average quiz scores. Today those numbers live in separate MongoDB collections, so computing them on the fly is slow. Please build a Spring Boot backend behind our GraphQL API that returns this profile for the authenticated student (OIDC). The service should first check a per-user Redis cache; on a miss, fetch and aggregate the data, produce a single JSON profile, store it with about a one-hour TTL, and return it. Subsequent requests should be served instantly from cache and keep the figures consistent.


Question: We want a behind-the-scenes security feature that regularly checks whether any of our users appear in public breach disclosures and, if so, requires a password reset and sends a clear security notice. Please build this as a Go (Gin) backend with MySQL. The service should run on a schedule, pull data from external breach feeds, and compare leaked identifiers (emails or usernames) to our user records without exposing or exporting our full user list. For matches, flag the account for a mandatory reset on the next login and write a detailed audit entry (who, when, which feed). Make the matching privacy-preserving and efficient (e.g., hashed/k-anonymized lookups), handle batching and retries for large feeds, and provide simple admin endpoints to review notifications and reset status.


Question: Authors should be able to publish a blog post and have it show up in their followers’ feeds shortly after. The create-post operation must be fast and should not wait on fan-out. After the post is saved, emit an event with postId and authorId to Kafka so a downstream service can insert the post into each follower’s feed in a time-ordered DynamoDB store (partition by userId, sort by timestamp). Build the write path only: a Spring Boot GraphQL mutation that persists the post and reliably publishes the Kafka message.


Question: We’re adding threaded conversations to our documents and tasks. Please build a backend that lets users post new comments and reply to existing ones, and returns the full nested discussion for a document in a single request. All actions must be tied to the signed-in user via an OAuth2 bearer token. Implement a REST API with Fastify (Node.js) and PostgreSQL: use a self-referencing schema (parent_comment_id) and a recursive CTE to assemble the complete comment tree. Provide endpoints to create a comment and to fetch the structured thread for a given document.


Question: Users expect the Explore page to surface trending hashtags almost instantly. We need a fast public endpoint that returns the current top 20 hashtags in under 50 ms without stressing our primary Postgres. The approach is to compute trends from recent posts on a schedule, write the results to Redis (e.g., a sorted set), and have an Express/Node API read only from that cache. Please define the data window for “recent,” the update cadence, tie-breaking rules, cache TTL/expiration, and the endpoint contract, plus how to handle failures if Redis or the job is unavailable. The goal is consistently fast reads and minimal load on the main database.


Question: We want customers to be proactively informed when something important changes in their dashboards. Please build a backend feature where users can create alert rules on a chart (e.g., value < 50), choose how often it’s checked (e.g., every 10 minutes), and select a notification channel (a webhook URL). Provide REST endpoints to manage rules, persist them in MongoDB using Micronaut. A scheduled evaluator should run in the background, group rules by chart to fetch data once per chart, evaluate conditions, and send notifications when thresholds are crossed. The evaluator must scale as rule counts grow, avoid duplicate or missed alerts, and expose metrics (job duration, rules processed, alerts sent, failures) to Prometheus for Grafana dashboards.


Question: We need a fast, user-friendly transaction history API for our banking app. Customers should be able to see their deposits, withdrawals, and transfers, filter by type and a date range, and keep scrolling without slowdowns—even as the table grows to tens of millions of rows. Use JWT for authentication and build with FastAPI. The endpoint is GET /v1/transactions and supports limit, an opaque cursor for infinite scroll, type, start_date, and end_date. Return a list of transactions and a next_cursor. To keep response times consistently low, use index-backed keyset (cursor) pagination—not offset—and create a composite B‑tree index on (user_id, created_at DESC) in PostgreSQL.


Question:
We’re building a patient-facing health dashboard where users can log daily vitals (e.g., systolic blood pressure, blood glucose) and later view chart-ready histories for a single metric over a selected date range. Please design a small REST API that supports this workflow:

- POST /v1/me/vitals: patients submit a reading with { type, value, unit, measuredAt }.
- GET /v1/me/vitals?type=...&from=...&to=...: returns the time series for that vital for the chosen window.

Authentication is via the patient’s JWT (Bearer). The service should strongly validate inputs to prevent unrealistic values or mismatched units and enforce well-formed timestamps. Use PostgreSQL and model the data for fast time-range queries as records grow; a composite index on (patient_id, type, measured_at) is expected. Focus on the API contract, validation rules, and schema that reliably feed charting in the dashboard; Go (Gin or similar) can be used for the implementation.


Question: Patients should get a comprehensive visit summary soon after an online consultation, without waiting on a slow API call. We need a flow where the request is accepted quickly, a task ID is returned, and the report is built in the background. Please outline a Spring Boot approach that publishes a "GenerateReport" job to RabbitMQ and exposes REST endpoints to create the task, check its status, and download the final report. Background workers will pull jobs, gather data from MySQL (historical EMR, recent notes, medications, billing), compile a PDF, store it, and update the job status (completed/failed). The system must stay responsive, be event-driven, and scale reliably to avoid timeouts.


Question: Add a validation endpoint to our project planner so that, before a plan is saved, the backend can verify that the submitted task dependencies don’t form a loop. The frontend will POST a JSON payload with tasks and their dependency links; the service should build a directed graph in memory and check for cycles (e.g., A → B → C → A). If a cycle is found, return a 400 with a clear message and the list or path of task IDs involved; otherwise return success. This needs to handle large plans without timing out. We’re on Java/Spring Boot with PostgreSQL, but this endpoint only validates the payload and doesn’t write to the database.