In one sentence
Replacing or cycling the API keys an application uses, either on a schedule for security or across several keys for failover, without breaking the apps that depend on them.
API key rotation means changing which key an application uses to call a service. The term covers two related jobs. Security rotation replaces a key with a new one on a schedule or after a leak, so an old key stops working. Operational rotation spreads requests across several keys or accounts and moves away from one that fails.
Security rotation
Keys leak through code commits, logs, screenshots and former staff. Rotating on a schedule limits how long a leaked key stays useful. The safe order is to create the new key, deploy it everywhere it is used, confirm traffic has moved, and only then revoke the old one. A central secret store or gateway makes this a single change instead of a hunt through every app.
Rotation and LLM rate limits
Many teams try rotating keys to get past 429 rate limit errors from AI providers. It usually does not work, because most providers count usage per account or project, not per key. OpenAI defines limits at the organization and project level, and Google's Gemini API applies rate limits per project, not per API key. Ten keys in one project share one limit. Getting past limits with extra accounts can also break a provider's terms. The supported paths are a higher usage tier or quota, fewer tokens per request, queuing, and retries with backoff.
Where operational rotation helps
A key can be revoked, run out of budget or start failing for reasons unrelated to load. A rotator that detects failures, sets the bad key aside and moves to the next healthy one keeps a workflow running. When a business already has separate projects for different clients, teams or regions, a gateway can route each request to the right one and log usage across all of them.
In practice
Keep provider keys out of application code, give apps one internal key to a gateway, alert on rising error rates, and document who can create and revoke keys. Our open-source Load Balancer and Vertex AI Load Balancer handle key and target rotation with failure detection and request logs; both are on our projects page.
Keep following the system
API Integration
A connection that lets software systems exchange approved data and invoke supported operations.
Subagent
A separate AI agent session that a main agent starts for one task, with its own context window, instructions and tools, which returns a short report when done.
AI Agent Governance
The rules, roles, limits and records that decide what an AI agent may do, who answers for it and how it is checked.
Model Context Protocol (MCP)
An open standard for connecting compatible AI applications to tools, resources, and prompts.
AI Agent
A system that uses a model and tools to pursue a goal across multiple steps within defined permissions and review boundaries.
Workflow Automation
Connecting business systems so repeatable tasks run according to defined rules and exceptions reach the right person.