Developer tools in Anytown & Area

It is source-available under the Fair Core License (FCL). You can read the code, run it and change it for your own use; what the licence rules out is offering it as a competing product. Each release becomes open source two years after it is published.

A caller cannot print, copy or exfiltrate a credential, because it never has one: keys live in one root-owned file the caller cannot read, the broker runs as its own user, and a caller cannot attach to its process. What it does not do is stop usage. A caller permitted to reach a service can use that service freely. That is why the caller list is mandatory per key, and why a write-capable credential is never listed for an agent's user.

No. A call is plain HTTP to a Unix socket with the service name as the first path segment. curl does it in one line; Python's standard library, Node's fetch and Go's net/http all speak it. Code that used to set an Authorization header deletes that line and keeps the rest.

It is refused before anything leaves the machine, and the refusal is written to the audit log with the same fields as a success. An unknown service is a 404, a caller not on the key's list or a path off the allowlist is a 403, a known path with the wrong method is a 405, and a caller over its rate limit is a 429. An upstream that cannot be reached is a 502.

Yes. Replace the key on the host and restart the service. Callers address a service by name, never by key, so nothing on their side changes. Replacing is a deliberate flag; adding to a label that already exists is refused so a rotation you did not intend cannot look like one you did.

In one config file, owned by root and readable only by the service. The service reads it itself — there is no environment file, because that would put every credential into the process environment for the life of the process. In memory, a key is held by one type that zeroes itself when dropped and has exactly one accessor.