Teller

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What Teller is

Teller is an open-source secret manager for developers working with secrets during app development, testing, and builds. It connects to vaults, key stores, and cloud services for individual environments or team workflows. Named integrations include HashiCorp Vault, AWS Secrets Manager, Google Secret Manager, HashiCorp Consul, AWS SSM, and dotenv providers; documentation also lists etcd and an in-memory store. The `teller run` command can launch a subprocess with variables fetched through Teller, while `teller env` can provide a Docker `--env-file`. Teller can scan code for secrets and return exit code 1 in CI when `--error-if-found` detects one. It can also redact secrets from process output, logs, live log tails, and files. Provider mappings can specify a root path, mapping ID, and optional key renames, and templates can use environment variables. The project offers release binaries and source installation with `cargo install --path .`. It is Apache-2.0 licensed.

Who it suits

Teller suits developers who need to manage secrets across development, testing, builds, or team environments. Its command-line options and provider integrations may also fit CI workflows that scan code or inject environment variables.

What it does well

Connects to named vault, cloud, and dotenv providers
Can supply variables to subprocesses
Can scan code for secrets in CI
Redacts secrets from logs and files

What to know first

Write operations depend on provider support
Opened pages establish Linux x86_64 testing, not other platform support

Limits

Write operations are available only for providers that support write use cases.

Plans

Plan	Billed and limits	Price
Teller	Open-source universal secret manager for developers	Free

As github.com lists them, read 4 Oct 2026. The maker's own page has the final word.

Getting started

Open the Teller GitHub project.
Download a release binary or install from source with `cargo install --path .`.
Configure provider mappings, including a root path, mapping ID, or key renames as needed.
Use `teller run` to start a subprocess with fetched variables.
Use `teller env` to supply a Docker `--env-file`, or run a secret scan in CI.

Verdict

Teller combines provider connections with secret scanning, environment injection, and redaction features. Note that writing values is limited to providers that support write use cases.

Questions

Is Teller free?

Yes. The project is free and open source under the Apache-2.0 license.

Which providers does Teller support?

Named providers include HashiCorp Vault, AWS Secrets Manager, Google Secret Manager, HashiCorp Consul, AWS SSM, and dotenv. The provider documentation also lists etcd and an in-memory store.

Which platforms does Teller support?

A 2025 issue reports testing Teller 2.0.7 on Linux x86_64.

Can Teller scan secrets in CI?

Yes. It can scan code, and the `--error-if-found` option returns exit code 1 when it finds a secret.

Can Teller write or delete provider values?

The project describes writing and deleting values, as well as copying or syncing mapped values. Write operations are limited to providers that support them.

How can I install Teller?

The project offers downloadable release binaries or a source installation method using `cargo install --path .`.

Facts from Teller's own pages

Configuration: Provider mappings can specify a root path, mapping ID, and optional key renames; configuration can use environment variables in templates. · github.com, 4 Oct 2026
Environment variables: The `teller run` command can run a subprocess with variables fetched through Teller, and `teller env` can supply a Docker `--env-file`. · github.com, 4 Oct 2026
Install: The project offers downloadable release binaries and a source installation method using `cargo install --path .`. · github.com, 4 Oct 2026
Integrations: The README names HashiCorp Vault, AWS Secrets Manager, Google Secret Manager, HashiCorp Consul, AWS SSM, and dotenv providers. · github.com, 4 Oct 2026
License: The GitHub repository identifies the project as Apache-2.0 licensed. · github.com, 4 Oct 2026
Notable limitation: The README says write operations are available only for providers that support write use cases. · github.com, 4 Oct 2026
Platform evidence: A 2025 issue reports testing Teller 2.0.7 on Linux x86_64; the opened pages do not establish support for other platforms. · github.com, 4 Oct 2026
Provider list: The provider documentation also lists etcd and an in-memory store. · docs.rs, 4 Oct 2026
Provider operations: The README describes copying or syncing mapped values, writing values to supported providers, and deleting values from providers. · github.com, 4 Oct 2026
Purpose: Teller is an open-source secret manager for developers working with secrets while developing, testing, and building apps. · github.com, 4 Oct 2026
Redaction: Teller can redact secrets from process output, logs, live log tails, and files. · github.com, 4 Oct 2026
Secret scanning: Teller can scan code for secrets and can be run in CI with `--error-if-found`, which returns exit code 1 when it finds something. · github.com, 4 Oct 2026
Use case: It connects to vaults, key stores, and cloud services to help manage secrets for an individual environment or team workflow. · github.com, 4 Oct 2026

Where Teller stands on Freedom251

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