AWS Secrets Manager vs Doppler

AWS Secrets Manager

IAM roles support access without long-lived credentials on AWS compute services. Each API call is billed, making caching relevant to frequent reads.

Doppler

Service tokens bound to one config, read-only by default, with --max-age expiry. Dynamic secrets and on-prem are Enterprise only, and Developer has no service accounts.

AWS Secrets Manager

1. Give the agent's task or instance role secretsmanager:GetSecretValue on the specific secret ARN, not a wildcard
2. Cache the value for the run, or read through the Workload Credentials Provider on localhost; each GetSecretValue is billed and logged
3. Use BatchGetSecretValue with a filter when you need several secrets at start-up; it's limited to 100 calls a second
4. Pass a ClientRequestToken on PutSecretValue so a retry can't create a second version, and don't write more than once every 10 minutes
5. Read VersionStage AWSPREVIOUS if a rotation lands mid-run and the new credential isn't live yet

Doppler

1. Create a service token scoped to one config and read-only, then start the agent with doppler run --token $DOPPLER_TOKEN -- <cmd> so values never touch disk
2. Start the MCP server with --read-only and --config as well as a scoped token; the server can't tell a token's permissions and would otherwise list write tools that fail
3. Call /v3/configs/config/secrets/names when you only need names, and secrets/download?format=json for every value in one call
4. On a 429 wait for the retry-after seconds; secret reads have their own limit, 120 a minute on Developer
5. Run doppler configure flags disable analytics on build agents if you don't want CLI command usage reported