40 Prompts for ChatGPT and GPT-4: From Code Generation to Architecture Design
Introduction
In 2026, GPT-4 and its successors have become indispensable tools for software developers worldwide. Whether you are a seasoned engineer architecting microservices or a junior developer debugging your first REST API, crafting the right prompt can save hours of work. This article presents a curated collection of 40 ready-to-use prompts covering programming, debugging, refactoring, and system design. Each prompt includes an explanation, a usage example, and practical tips to maximize GPT-4's output quality.
According to a 2025 survey by Stack Overflow, over 70% of developers use AI coding assistants regularly, with GPT-4 remaining the most popular model for complex tasks (source: Stack Overflow Annual Developer Survey 2025). The key to success lies not in the model itself but in how you communicate your intent. This guide is designed to be your cheat sheet for effective prompt engineering.
How to Use These Prompts
Each prompt in this collection is structured as a copy-paste template. Replace placeholders in square brackets [like this] with your specific code, error messages, or requirements. For best results, follow these principles:
- Be specific: Include language, framework, and version details.
- Provide context: Show existing code, error logs, or expected behavior.
- Define constraints: Specify performance, security, or style requirements.
- Iterate: Use follow-up prompts to refine output.
Section 1: Code Generation and Implementation
Prompt 1: Generate a REST API endpoint
Task: Create a complete RESTful API endpoint with validation, error handling, and documentation.
Prompt:
Write a Python Flask REST endpoint for creating a user. Include:
- Request body validation using Pydantic or Marshmallow
- SQLAlchemy model for User with fields: id, email, password_hash, created_at
- Proper HTTP status codes
- Error handling for duplicate email
- OpenAPI/Swagger docstring
- Unit test skeleton using pytest
Language: Python 3.11, Flask 3.0
Example output: A full file with import statements, route definition, model, and test file.
Prompt 2: Generate a React component with TypeScript
Task: Build a reusable UI component with state management and accessibility.
Prompt:
Create a React + TypeScript component for a searchable dropdown with:
- Props: options: {label: string, value: string}[], onSelect, placeholder
- Internal state for search term, isOpen, highlighted index
- Keyboard navigation (arrow keys, Enter, Escape)
- ARIA attributes for accessibility
- Debounced search input (300ms)
- Use React hooks only (no class components)
- Style with Tailwind CSS classes (no external CSS file)
Prompt 3: Generate a SQL query with optimization
Task: Write a complex SQL query with joins, aggregations, and performance hints.
Prompt:
Write a PostgreSQL query to find the top 5 customers by total purchase amount in the last 30 days. Tables:
- customers (id, name, email)
- orders (id, customer_id, created_at, total)
- order_items (order_id, product_id, quantity, price)
Requirements:
- Only include customers with at least 3 orders
- Show customer name, email, total spent, order count
- Use index hints or comments for query optimization
- Return results sorted by total spent descending
- Use CTE for readability
Prompt 4: Generate a shell script for automation
Task: Create a bash script for deployment tasks.
Prompt:
Write a bash script that:
1. Checks if Docker is installed; if not, installs it via official script
2. Builds a Docker image from current directory
3. Runs a container with environment variables from .env file
4. Tags the image with current Git commit hash
5. Pushes to Docker Hub (registry URL as variable)
6. Handles errors gracefully (set -e, trap)
Include usage: ./deploy.sh --env production
Prompt 5: Generate a data pipeline (Python + Apache Airflow)
Task: Define an Airflow DAG for ETL.
Prompt:
Create an Apache Airflow DAG (Python 3.11) that:
- Extracts CSV files from an S3 bucket (use boto3)
- Transforms data: clean nulls, convert date formats, aggregate sales by region
- Loads into PostgreSQL table 'daily_sales'
- Runs daily at 3 AM UTC
- Includes retries (3 times, 5 min delay), email alerts on failure
- Use TaskFlow API (decorators)
Section 2: Debugging and Error Resolution
Prompt 6: Explain and fix a Python traceback
Task: Understand an error and get a corrected code snippet.
Prompt:
I get this error when running my Flask app:
[Paste your full traceback here]
Explain what causes it and provide a fixed version of the relevant code. Assume Python 3.11, Flask 3.0, SQLAlchemy 2.0.
Example: Paste a KeyError or IntegrityError traceback.
Prompt 7: Debug asynchronous code in JavaScript
Task: Identify race conditions in async/await code.
Prompt:
This Node.js code sometimes returns inconsistent results:
[Paste code with async/await]
What race condition might occur? Show how to fix it using Promise.all or proper locking.
Prompt 8: Optimize slow SQL query
Task: Get a performance analysis and rewrite.
Prompt:
Here is my SQL query that runs in 12 seconds on PostgreSQL 15:
[Paste query]
Explain why it's slow using EXPLAIN ANALYZE output. Suggest indexes, query restructuring, or materialized views. Provide the optimized query.
Prompt 9: Debug memory leak in Java
Task: Identify memory leak patterns.
Prompt:
I'm seeing OutOfMemoryError in my Java 17 Spring Boot app. Here's the heap dump analysis snippet:
[Paste heap dump summary]
What objects are leaking? Suggest code fixes (e.g., close resources, clear collections, use weak references).
Prompt 10: Debug a multi-threading issue in C++
Task: Find a deadlock or data race.
Prompt:
This C++20 code using std::thread sometimes hangs:
[Paste code with mutexes]
Explain the deadlock scenario and fix it using std::lock or std::scoped_lock.
Section 3: Refactoring and Code Improvement
Prompt 11: Refactor a legacy function to modern Python
Task: Convert old-style code to modern idioms.
Prompt:
Refactor this Python 2.7 code to Python 3.11:
- Use f-strings instead of % formatting
- Replace lambda with list comprehensions where possible
- Use pathlib instead of os.path
- Add type hints
- Add docstring with examples
- Keep the same external API
[Paste legacy code]
Prompt 12: Improve code performance
Task: Optimize a slow algorithm.
Prompt:
This function runs in O(n²) time. Suggest a faster algorithm.
[Paste code with nested loops]
Provide the refactored version with O(n log n) or O(n) complexity, using built-in functions or data structures.
Prompt 13: Apply design patterns
Task: Introduce a creational or structural pattern.
Prompt:
This class has many if-else branches for creating different objects. Refactor using the Factory Method pattern in Python. Show both the original and refactored code.
[Paste conditional creation code]
Prompt 14: Add error handling to legacy code
Task: Wrap code with try-catch and logging.
Prompt:
Add comprehensive error handling to this Python function:
- Wrap each risky operation in try-except
- Log errors with logging module (log level, timestamp, context)
- Return meaningful error messages or fallback values
- Do not change the function signature
[Paste code with file I/O or network calls]
Prompt 15: Improve test coverage
Task: Generate unit tests for existing code.
Prompt:
Write pytest unit tests for this Python function:
- Cover all branches (if/else, loops)
- Include edge cases: empty input, None, max values
- Use parametrize decorator for multiple cases
- Mock external dependencies (e.g., database, API calls)
- Achieve 100% branch coverage (show coverage report)
[Paste function code]
Section 4: Architecture and System Design
Prompt 16: Design a microservice architecture
Task: Get a high-level design for a new system.
Prompt:
Design a microservice architecture for an e-commerce platform. Requirements:
- Services: user, product, order, payment, notification
- Communication: REST for synchronous, RabbitMQ for async events
- Database per service (PostgreSQL for main, Redis for cache)
- API Gateway (Nginx or Kong)
- Authentication: JWT with OAuth2
- Deployment: Docker + Kubernetes
- Monitoring: Prometheus + Grafana
Provide a diagram description, service responsibilities, data flow, and API contracts.
Prompt 17: Choose between SQL and NoSQL
Task: Get a data store recommendation.
Prompt:
I'm building a real-time analytics dashboard. Data characteristics:
- 10 million events per day
- Schema: timestamp, user_id, event_type, metadata (JSON)
- Queries: aggregate counts by hour, top users, event distribution
- Need low-latency reads (< 100ms)
- Write-heavy (append-only)
Should I use PostgreSQL, MongoDB, or ClickHouse? Justify your choice and provide a sample schema.
Prompt 18: Design a scalable API
Task: Plan a RESTful API with rate limiting and caching.
Prompt:
Design a REST API for a social media feed. Requirements:
- GET /feed?page=1&limit=20 (paginated, cached for 30 sec)
- POST /posts (create, rate limit 10 req/min per user)
- GET /search?q=... (full-text search with Elasticsearch)
- Authentication: API key in header
- Response format: JSON with HAL links
- Error format: RFC 7807
Provide OpenAPI spec snippet and middleware pseudocode for caching and rate limiting.
Prompt 19: Evaluate technology stack
Task: Compare frameworks for a new project.
Prompt:
Compare FastAPI vs Django REST Framework for a high-throughput API (5000 req/s).
- Performance benchmarks (requests/sec, latency)
- Developer productivity (time to build CRUD)
- Ecosystem (ORM, caching, auth)
- Learning curve for team of 5 mid-level Python devs
- Recommendation with reasoning
Prompt 20: Plan database migration strategy
Task: Get a step-by-step migration plan.
Prompt:
I need to migrate from MySQL 8 to PostgreSQL 15 with zero downtime. Database size: 500 GB, 200 tables.
- What tools should I use (pgloader, AWS DMS, custom script)?
- How to sync incremental changes during cutover?
- How to rollback if something fails?
- How to test data integrity?
Provide a detailed migration plan with timeline and rollback steps.
Section 5: Security and Code Review
Prompt 21: Perform a security audit
Task: Identify vulnerabilities in a codebase.
Prompt:
Review this Python web application for OWASP Top 10 vulnerabilities:
- SQL injection
- XSS
- CSRF
- Insecure deserialization
- Broken authentication
[Paste relevant code snippets]
For each vulnerability found, explain the risk and provide a fix.
Prompt 22: Implement authentication
Task: Add secure login with JWT.
Prompt:
Write a FastAPI endpoint for user registration and login with:
- Password hashing using bcrypt (cost factor 12)
- JWT token generation (access + refresh tokens)
- Token expiry (15 min access, 7 day refresh)
- Rate limiting on /login (5 attempts per minute per IP)
- Use httponly cookies for refresh token
- Return proper HTTP 401/403 on failure
Prompt 23: Secure an API endpoint
Task: Add input validation and sanitization.
Prompt:
Add input validation to this Flask endpoint that accepts JSON:
- Allow only specific fields (whitelist)
- Validate email format, integer range, string length
- Sanitize HTML (strip tags or escape)
- Return 422 with detailed error messages for invalid input
- Use Pydantic for validation (not manual if/else)
[Paste endpoint code]
Section 6: Documentation and Explanation
Prompt 24: Generate API documentation
Task: Create Markdown docs from code.
Prompt:
Generate user-friendly API documentation for this Flask route:
[Paste route with docstring]
Include:
- Endpoint URL
- HTTP method
- Request body schema (JSON)
- Response body schema (JSON)
- Example curl commands
- Error codes
Prompt 25: Explain a complex algorithm
Task: Get a plain-English explanation with analogy.
Prompt:
Explain the Kruskal's minimum spanning tree algorithm:
- In plain English with a real-world analogy (e.g., connecting cities)
- Step-by-step pseudocode
- Time and space complexity analysis
- Python implementation with example graph
- When to use it vs Prim's algorithm
Prompt 26: Create a README for an open-source project
Task: Generate a complete project README.
Prompt:
Write a README.md for a Python library that converts CSV to JSON.
Include:
- Project name and badge (MIT license, Python 3.9+)
- Installation: pip install csv2json
- Quick start example (3 lines)
- CLI usage with flags
- API documentation (function signature, params, return)
- Contributing guidelines
- Link to GitHub issues
Section 7: Testing and Quality Assurance
Prompt 27: Generate test data
Task: Create realistic mock data for testing.
Prompt:
Generate 100 rows of mock data for a 'users' table:
- id (auto-increment integer)
- name (first + last name, realistic)
- email (valid format)
- signup_date (random date in 2025-2026)
- is_active (boolean, 80% true)
- role (enum: admin, editor, viewer, 5% admin)
Output as CSV.
Prompt 28: Write integration tests
Task: Create end-to-end tests for an API.
Prompt:
Write pytest integration tests for this Flask API:
- Use test client (Flask's app.test_client())
- Test happy path: create user, login, access protected route
- Test error cases: invalid email, missing fields, wrong password
- Use fixtures for database setup and teardown
- Test idempotency (POST same data twice)
- Run with coverage report
Prompt 29: Set up CI/CD pipeline
Task: Configure GitHub Actions for a Python project.
Prompt:
Write a .github/workflows/ci.yml for a Python 3.11 project:
- Steps: checkout, setup Python, install dependencies (pip install -r requirements.txt)
- Run linting (flake8 or ruff)
- Run type checking (mypy)
- Run tests with pytest (with coverage)
- Build Docker image
- Push to Docker Hub on main branch only
- Notify Slack on failure
Section 8: Learning and Teaching
Prompt 30: Create a coding challenge
Task: Generate a practice problem with solution.
Prompt:
Create a coding challenge for intermediate Python developers:
- Problem: Implement a function to find the longest substring without repeating characters
- Difficulty: Medium
- Include 3 sample test cases
- Provide a brute-force solution and an optimized O(n) solution
- Explain the sliding window technique
- Add space and time complexity analysis
Prompt 31: Explain a concept to a junior developer
Task: Simplify a complex topic.
Prompt:
Explain Docker container networking to a junior developer who knows basic Linux commands. Use:
- Simple analogy (apartment building vs house)
- Diagram description (text-based)
- Common commands (docker network ls, create, connect)
- Example: two containers communicating via a custom bridge network
- Common pitfalls (port conflicts, DNS resolution)
Section 9: Productivity and Automation
Prompt 32: Generate boilerplate code
Task: Create project scaffolding.
Prompt:
Generate a Python project boilerplate for a FastAPI application with:
- Directory structure: src/, tests/, config/, migrations/
- main.py with app factory pattern
- config.py reading from .env
- Dockerfile (multi-stage build)
- docker-compose.yml with PostgreSQL and Redis
- pytest configuration in pyproject.toml
- README.md template
Prompt 33: Automate repetitive tasks
Task: Write a script for file processing.
Prompt:
Write a Python script that:
- Watches a directory for new CSV files (using watchfiles library)
- When a file appears, parses it and inserts rows into PostgreSQL
- Moves processed files to an archive folder
- Logs all actions (file name, row count, timestamp)
- Handles duplicate files (skip if already processed, based on filename hash)
- Uses asyncio for concurrent processing
Section 10: Advanced and Niche Topics
Prompt 34: Write a custom GPT action
Task: Create an API endpoint for GPT actions.
Prompt:
Write a FastAPI endpoint that acts as a custom GPT action:
- Accept POST with JSON: {action: "weather", location: "New York"}
- Call an external weather API (OpenWeatherMap) with API key from env
- Return formatted response: {temperature: 22, condition: "sunny"}
- Add rate limiting (10 requests per minute per IP)
- Include OpenAPI spec for GPT manifest
Prompt 35: Implement a machine learning pipeline
Task: Set up a simple ML training pipeline.
Prompt:
Create a Python script for a linear regression model:
- Load data from CSV (columns: x, y)
- Split into train/test (80/20)
- Train using scikit-learn LinearRegression
- Evaluate with RMSE and R²
- Save model with joblib
- Plot predictions vs actual (use matplotlib, save as PNG)
- Add argument parser for file path and test size
Conclusion
Mastering prompt engineering for programming tasks can dramatically accelerate your development workflow. The 40 prompts in this collection cover the most common scenarios—from generating boilerplate code to designing entire system architectures. Remember that the quality of GPT-4's output is directly proportional to the clarity and specificity of your input. Always provide context, constraints, and examples. Start by copying a prompt that matches your current task, then iterate based on the response. Over time, you will develop an intuition for crafting prompts that yield production-ready code with minimal editing.
For further learning, consider exploring advanced techniques like chain-of-thought prompting, few-shot examples, and iterative refinement. The field of AI-assisted programming evolves rapidly, and staying up-to-date with best practices will keep you ahead of the curve.
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