Create or update a repository Actions secret via the GitHub REST API (encrypted_value + key_id)
domain: docs.github.com · 6 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Authenticate with a PAT that has the repo scope (or a GitHub App token with secrets:write+actions:write). Send an Authorization: Bearer <TOKEN> header and Accept: application/vnd.github+json.
Fetch the repository public key: GET https://api.github.com/repos/{owner}/{repo}/actions/secrets/public-key — capture key_id and key (base64) from the response.
Encrypt the plaintext secret value into a libsodium sealed box (NaCl crypto_box_seal) using the base64-decoded public key, then base64-encode the ciphertext as encrypted_value. The secret is never sent in plaintext.
Create or update: PUT https://api.github.com/repos/{owner}/{repo}/actions/secrets/{secret_name} with body {"encrypted_value": "...", "key_id": "..."}.
201 Created means a new secret was added; 204 No Content means an existing secret was updated. Secret names are case-insensitive and stored lowercase.
Confirm via GET /repos/{owner}/{repo}/actions/secrets/{secret_name} — note the value is never returned; only name/created_at/updated_at metadata is readable.
Known gotchas
Encryption is mandatory — sending the plaintext value causes a 422 error; you must encrypt with the public key and pass both encrypted_value and key_id.
The public key changes when secrets are added, so always re-fetch the key before each create/update rather than caching it.
Secret values cannot be read back after being set; the API only exposes names and timestamps.
Secret names must match the documented regex; names are case-insensitive (stored lowercase) and cannot be reused with different casing.
Connecting an environment-level or org-level secret with the same name shadows the repository value inside that environment/org scope.
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