Cursor OpenAI API key not working

What this error means

API key not working means the API or AI coding tool rejected the request because credentials, model access, quota, context size, or provider configuration does not match the request being sent.

Why this happens

OpenAI-compatible tooling usually has three moving parts: API key, selected model, and request size.

For Cursor OpenAI API key not working, debug the smallest request that uses the same provider, model, and environment variable.

Common causes

• API key was pasted into the wrong provider field
• Provider base URL is incorrect
• Key lacks access to the selected model
• Application needs to be restarted after settings change

Quick fixes

1. Verify the API key is present without printing its value.
2. Check the configured model name and provider/base URL.
3. Verify the provider, API key, base URL, and model selection, then restart Cursor before retrying.
4. Retry with a minimal request before rerunning the full app or editor workflow.

Copy-paste commands

Check whether the key is set

printf "OPENAI_API_KEY=%s\n" "${OPENAI_API_KEY:+set}"

Send a minimal API request

curl https://api.openai.com/v1/models \
  -H "Authorization: Bearer $OPENAI_API_KEY"

Inspect app environment without exposing the key

env | grep -E "OPENAI|MODEL|BASE_URL" | sed "s/=.*/=<redacted>/"

Platform-specific fixes

CI/CD

• Set API keys as CI secrets, then restart or rerun the job so the process reads the updated environment.

Real-world fixes

• If a tool works in one editor window but not another, compare provider settings and restart the editor.
• If a model fails but authentication works, test a known available model before changing application code.
• Verify the provider, API key, base URL, and model selection, then restart Cursor before retrying.

Step-by-step troubleshooting

1. Record the request path, model, and API key not working without logging secret values.
2. Verify OPENAI_API_KEY or the provider-specific key exists in the process that sends the request.
3. Send a minimal API request with curl to separate SDK bugs from account or credential issues.
4. If the error mentions context, reduce prompt history and requested output tokens.
5. If the error mentions quota or rate limits, reduce concurrency before requesting higher limits.

How to prevent it

• Centralize model names and provider base URLs in configuration.
• Add retry backoff for rate-limit errors, not for quota or credential errors.
• Log request IDs and non-secret configuration for production debugging.

Related errors

• OpenAI API invalid API key
• OpenAI API model not found
• OpenAI API insufficient quota

FAQ

What should I check first?

Start with the exact API key not working line and the command, request, or workflow step that produced it. In OpenAI API or AI coding tool, the first useful clue is usually near the first failure line, not the final stack trace.

Can I ignore this error?

No. Treat it as a failed OpenAI API or AI coding tool step. A temporary bypass may help diagnosis, but the underlying cause should be fixed before shipping or publishing changes.

Why does this work locally but fail elsewhere?

Local machines often have cached credentials, old dependencies, different runtime versions, or network settings that CI and production do not share. Reproduce from a clean shell or clean install when possible.

How do I know the fix worked?

Rerun the smallest command, request, or deployment step that produced API key not working. The fix is working when that step completes without the same signature and produces the expected output.