Claude vs GitHub Copilot: Which AI Writes More Secure Code?

We gave Claude, GitHub Copilot, and ChatGPT the same 100 coding prompts covering security-sensitive scenarios:

• Authentication and authorization
• Database queries
• File handling
• API endpoints
• Cryptography
• Input validation

Each response was scored on functionality, security, and best practices.

Key Findings

Claude produced the most secure code overall, with 72% of responses free from security vulnerabilities. However, no AI achieved above 75%—meaning all of them generate vulnerable code regularly.

When asked to write database queries:

Claude was most likely to use safe query patterns, but still failed 15% of the time.

When creating API endpoints:

Claude was most likely to include both authentication AND authorization checks, though still failed 35% of the time.

1. Constitutional AI Training

Claude is trained with safety-focused principles that include security considerations.

2. Longer Context Window

Claude maintains context over longer conversations, remembering security requirements mentioned earlier.

3. Explicit Reasoning

Claude often proactively explains security considerations it included.

Despite Claude's lead, none of these tools should be trusted blindly:

1. Training data includes vulnerable code - All models learned from the internet
2. Optimization for functionality - AI prioritizes "does it work?" over "is it secure?"
3. No threat modeling - AI doesn't understand your specific security requirements

If You Use Claude

• Best for: Complex logic, security-sensitive code
• Still scan: Claude misses vulnerabilities 28% of the time
• Pro tip: Ask Claude to review its own code for security issues

If You Use Copilot

• Best for: Quick completions, boilerplate code
• Higher risk: More likely to suggest vulnerable patterns
• Required: Always review authentication and database code

If You Use ChatGPT

• Best for: Explanations, learning, exploring approaches
• Moderate risk: Better than Copilot, worse than Claude

Claude writes more secure code than Copilot or ChatGPT, but still produces vulnerabilities in 28% of security-sensitive tasks.

The safest approach:

1. Use Claude for complex, security-sensitive code
2. Ask it to explain security considerations
3. Scan everything with ShipReady before deploying

No AI is secure enough to trust without verification. Ship with confidence—scan your code.