Fly Secrets (ENV)

When to use this page

• You need to store runtime secrets for a Fly application.
• You want secure secret updates without rebuilding the image.

Prerequisites

• Fly app is created.
• flyctl is authenticated to the correct organization.
• Secret values are prepared and validated.

Fly Secrets are encrypted environment variables available at runtime. Use them for API keys, database URLs, tokens, and other sensitive values.

Documentation: https://fly.io/docs/apps/secrets/

Managing secrets

You can manage secrets either through the Fly Dashboard UI or via the CLI.

Setting secrets

fly secrets set SECRET_KEY=value

You can set multiple secrets at once:

fly secrets set DATABASE_URL=postgres://... REDIS_URL=redis://...

Listing secrets

fly secrets list

This shows secret names and their last updated timestamps. Values are never displayed.

Removing secrets

fly secrets unset SECRET_KEY

Verify

• fly secrets list shows all required keys.
• App restart picks up new values after secret changes.
• Application health checks still pass after updates.

Troubleshooting

• Secret appears set but app still uses old value: Confirm app restart completed and no duplicate env source overrides it.
• Accidentally removed secret: Re-add immediately and redeploy if startup fails.