"Build a REST API with Express.js, TypeScript, Zod validation, and Prisma ORM for a todo app"
GPT-4o generates a complete, well-typed Express API with proper Zod schemas, Prisma models, error handling middleware, and correct TypeScript generics. Code runs with minimal fixes — one missing import.
Gemini 2.5 Pro produces a working API but uses 'any' in two handler signatures and misses the Prisma client generation step in setup instructions. More boilerplate comments than necessary.
Why Tie wins: ChatGPT's output was closer to production-ready with stricter TypeScript and fewer manual fixes needed.
"Refactor this 2,000-line React component into smaller components with proper prop types"
GPT-4o identifies the key extraction points and creates well-named components with clean prop interfaces. However, it can only process about half the file at once due to context limits, requiring multiple passes.
Gemini 2.5 Pro processes the entire file in one shot thanks to its 1M context window. It identifies more refactoring opportunities and produces a complete component tree with consistent naming.
Why Tie wins: Gemini's ability to hold the entire file in context produced a more coherent refactoring plan — no split-pass inconsistencies.
"Debug this Python script that's throwing a race condition in async database writes"
GPT-4o correctly identifies the race condition, explains the execution order issue, and provides a fix using asyncio.Lock with proper context manager syntax. Also suggests connection pooling improvements.
Gemini 2.5 Pro identifies the issue but suggests a broader fix that includes unnecessary restructuring. The core fix is correct but buried in extra changes that could introduce new bugs.
Why Tie wins: ChatGPT's fix was surgical — it addressed exactly the race condition without over-engineering the solution.
"Write comprehensive unit tests for this payment processing module (150 lines of code)"
GPT-4o generates solid tests but relies heavily on mocking — mocks the payment gateway, database, and email service. Tests pass but wouldn't catch integration issues.
Gemini 2.5 Pro generates more tests with better edge case coverage, including tests for decimal precision, currency conversion, and idempotency. Still uses mocks but achieves higher branch coverage.
Why Tie wins: Gemini generated more thorough edge case tests and achieved better coverage, especially for payment-specific edge cases like decimal rounding.
"Set up a CI/CD pipeline with GitHub Actions for a Next.js app with Playwright tests"
GPT-4o produces a clean YAML workflow with proper caching, parallel test runs, and deployment steps. Syntax is correct and ready to commit.
Gemini 2.5 Pro generates a similar workflow but adds more detailed comments explaining each step. Includes a matrix strategy for multiple Node versions that wasn't requested but is useful.
Why Tie wins: ChatGPT's output was leaner and immediately usable. Gemini's extras were helpful for learning but added unnecessary complexity for the task.
Compare GPT-4o and Gemini 2.5 Pro for coding with your own prompts — free.
Try NailedIt.ai →