Missing secret_key_base for 'production' environment Ruby / Rails Origin: Application & API OSI layer 7 · Application Last updated 5 Nov 2026

Rails: ArgumentError: Missing `secret_key_base` for 'production' environment, set this string with `bin/rails credentials:edit`

Production boot needs a secret_key_base to sign/encrypt cookies, and none is configured.

Exact message you may see Missing `secret_key_base` for 'production' environment, set this string with `bin/rails credentials:edit`ArgumentError: Missing `secret_key_base` for 'production' environmentMissing secret_key_base for production environmentArgumentError (Missing `secret_key_base` for 'production' environment, set this value in `config/secrets.yml`)Missing secret_key_base
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Seen on: Ruby

Meaning

Provide SECRET_KEY_BASE as an environment variable (generate with bin/rails secret), or set it in credentials.yml.enc with RAILS_MASTER_KEY. For asset precompilation in Docker use SECRET_KEY_BASE_DUMMY=1. Keep the same value across servers so sessions remain valid.

Common causes

  • SECRET_KEY_BASE/credentials not set in production
  • Master key missing so credentials unreadable
  • Docker precompile step without a dummy key
  • Different keys across servers
  • Env var name typo

⚡ Quick fix

  1. export SECRET_KEY_BASE=$(bin/rails secret) (store it securely)
  2. Or ship credentials.yml.enc + RAILS_MASTER_KEY
  3. SECRET_KEY_BASE_DUMMY=1 for precompile only

Detailed fix by platform

Rails

  1. bin/rails secret generates a 128-hex-character key

How to diagnose

  1. Variable — Set in prod?
  2. Credentials — Readable?
  3. Build — Dummy?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Application & API. Errors that are often confused with or caused by this one (click to open):

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