An 'API key expired' Error Doesn't Always Mean Expired. Check Which Key Is Actually Sent Before You Renew It
A 400 with API_KEY_INVALID from the Gemini API cannot tell you whether the key expired or something else is wrong. A small diagnostic script checks env-var precedence and stray quotes first, run here against dummy keys.
My ADK Agent Never Ran and Said 'API key expired' — Reading the Reason Code Gave Me a Triage Order
When ADK returns 400 INVALID_ARGUMENT 'API key expired. Please renew the API key.' on every run, check this order before assuming the key expired: read the reason code, compare shell and .env keys by their last four characters, then test the key alone over REST.
Locking Down a Gemini API Key on Servers Whose IP Keeps Changing — Restrictions for Headless Automation
After unrestricted keys started getting blocked, headless server automation whose egress IP changes every run can't cleanly use HTTP referrer, app restrictions, or an IP allowlist. Do you get by with API restrictions alone, funnel egress through a fixed IP, or move server workloads off API keys onto Vertex service-account auth? A decision framework and working code, without taking your pipelines down.
Audit Your Gemini API Key Restrictions Before the Unrestricted-Key Block Stops Your Automation
Since June 19, 2026, requests from unrestricted Gemini API keys are blocked. Here is how to check whether your key is affected and add restrictions without taking your production automation down.
Rotating Gemini API Keys with Zero Downtime in Production
A practical playbook for rotating Gemini API keys without dropping production traffic. Covers dual-key fallback, Cloudflare Workers Secrets, automatic failover clients, and the first sixty minutes of a leak response.
Gemini API Authentication Errors: Causes and Solutions
Complete guide to diagnosing and fixing Gemini API authentication errors including 401/403 status codes, API key issues, and permissions.