BYOK AI Explained: Why Bringing Your Own Key Matters for Code Review
BYOK — Bring Your Own Key — is increasingly a requirement for enterprise AI tooling. But what does it actually mean in practice, and why does it matter specifically for AI code review? Here's a clear explanation of BYOK and why Merlin AI Code Review was built around it from day one.
What BYOK means
In the context of AI developer tools, BYOK means the tool uses your organization's own API key to call AI providers — rather than routing your requests through the vendor's own AI backend. The distinction sounds subtle but has significant implications.
Without BYOK: Your data → Vendor server → Vendor's AI key → AI provider → Results → Vendor server → You. Your code passes through and is potentially stored by the vendor.
With BYOK (Merlin AI Code Review): Your data → Your CI runner → Your AI key → AI provider → Results → Your CI runner → Your PR. No vendor intermediary.
Why it matters for code review
Code is among the most sensitive intellectual property a company possesses. Source code contains business logic, security-critical systems, proprietary algorithms, and sometimes inadvertently leaked credentials or configuration. Sending it to a third-party vendor creates several risks:
- Vendor breach — if the vendor is compromised, so is your code
- Training data usage — some vendors use your data to train future models without explicit consent
- Retention policies — code may be retained for audit, debugging, or legal purposes you didn't intend
- Regulatory exposure — a vendor receiving your data is a data processor under GDPR, requiring a DPA
BYOK eliminates the vendor as a data processor. Your code travels directly from your infrastructure to the AI provider — the same provider your team already uses and has assessed.
BYOK with your enterprise agreement
Most enterprises already have (or can negotiate) enterprise agreements with AI providers like Anthropic or OpenAI. These agreements typically include:
- Data Processing Addendums (DPAs)
- Opt-out from training data usage
- Data retention limits
- SOC2/ISO27001 compliance documentation
When Merlin AI Code Review uses your API key under your enterprise agreement, these protections apply. A vendor that uses their own AI key does not give you access to these contractual protections.
Which providers does Merlin AI Code Review support?
Merlin AI Code Review supports BYOK for all major AI providers:
- Anthropic Claude — set
ANTHROPIC_API_KEY - OpenAI GPT-4o — set
OPENAI_API_KEY - Google Gemini — set
GEMINI_API_KEY - AWS Bedrock — set
AWS_ACCESS_KEY_ID+AWS_SECRET_ACCESS_KEY - Ollama — no key at all; fully local inference
For the most privacy-sensitive workloads, Ollama enables running capable open-source models entirely on-premises — zero data leaves your network during inference.
Key rotation and revocation
With BYOK, you control the key lifecycle. If a key is compromised, you revoke it immediately through the provider's console — no vendor coordination required. You can scope keys to specific permissions, set spending limits, and audit usage through the provider's dashboard. This level of control is impossible when a vendor uses their own pooled key.