Claude Code vs ChatGPT Code — Which AI Should Build Your Features?

I tested both on the same codebase for 3 weeks straight. Here's what I learned about when to use each one.

The Setup

Over the past month, we shipped 40K+ lines of production code using both Claude Code (via Codex CLI) and ChatGPT Pro. This isn't academic—it's what we learned building BuildrFlags, a feature flag SaaS, and Buildr HQ, our internal command center.

We're also burning about $200/month on Anthropic Max and $20 on ChatGPT Pro. So I had to figure out when each was worth it.

The Benchmarks

Speed to First Deploy

• Claude Code: ~4 minutes per feature (includes tests, types, validation)
• ChatGPT Code: ~6 minutes per feature (requires back-and-forth on types)
• Edge: Claude by 33%

That sounds small until you do the math: in a 24-hour sprint at 10 features, Claude saves ~20 minutes. Not huge, but every bit counts.

Code Quality (Test Coverage)

• Claude Code: 80–90% test coverage, types-first approach
• ChatGPT Code: 60–75% coverage, more exploratory
• Edge: Claude for systems that matter

Real-world data from our codebase: 1 production bug from Claude-generated code. 4 from ChatGPT in the same period.

This matters if you're shipping to customers. It doesn't matter much if you're spiking.

Refactoring Existing Code

• Claude Code: Understands context, respects patterns, suggests improvements
• ChatGPT Code: Sometimes over-rewrites things that aren't broken
• Edge: Claude

Claude reads the file first. ChatGPT asks you to paste snippets. That's a real difference in how much context you're giving it.

Token Cost

Here's where it gets weird:

• Claude Code: ~$0.05 per feature when you're on Anthropic Max
• ChatGPT Code: ~$0.03 per feature in raw API costs
• Edge: ChatGPT if cost is all that matters

But if you're paying $200/month for unlimited Anthropic Max anyway, Claude is free. And if you need fast iterations, ChatGPT Pro ($20/month) is unlimited too.

Our reality: we pay both subscriptions. The question isn't "which is cheaper," it's "which is faster for what I'm building right now."

Where Each One Wins

Use Claude Code For:

• SDK development — It expects types, tests, and validation without you asking
• Complex refactoring — Understands your codebase patterns
• Security work — Crypto, auth, payments; you want it "correct," not creative
• PRs under 500 lines — Focused work where it can nail the requirements
• When you need it right the first time — Ship code you trust immediately

Use ChatGPT Code For:

• Spikes and prototypes — "What's the fastest way to build this?"
• Learning new libraries — Explanation + code in the same chat
• Exploration — "I'm not sure exactly what I want yet"
• Long, complex features — Chat mode lets you iterate without typing requirements
• When you're burned out — Sometimes talking through it is faster than prompting

The Gotchas

Claude Code Can Be Conservative

It won't try risky optimizations. It sometimes over-engineers small features. And vague prompts get vague code—you have to be specific.

Solution: Write a proper PRD. Spend 2 minutes describing what you want. Claude will ship it correctly.

ChatGPT Code Can Be Creative

"Creative" means hallucinating library APIs when it's not 100% sure. It means trying things that sound right but aren't. And the token limit means it forgets context in long sessions.

Solution: Verify everything. It's great at brainstorming, but you're the final editor.

How We Decided

We built a simple decision tree:

Production + security-critical?     → Claude Code
< 200 lines of clear logic?         → Claude Code
SDK / public API?                   → Claude Code
Spike or POC?                       → ChatGPT (faster)
Claude timed out?                   → ChatGPT (fallback)
You want to chat vs. prompt?        → ChatGPT (saves typing)

The result: 80% Claude, 20% ChatGPT. Claude for anything that touches production. ChatGPT for thinking out loud.

The Verdict

Both work. Claude is more reliable. ChatGPT is more flexible.

If you're serious about shipping fast, get both:

• Claude: Anthropic Max ($200/month) = unlimited coding
• ChatGPT: Pro ($20/month) = unlimited exploration

We've shipped in production with both. Claude's code needs fewer revisions. ChatGPT's exploration saves time on features you're unsure about.

Pick the right tool for the job. Both are better than writing it yourself.