Busbar 1.0.0-rc.1, the first release candidate

A few weeks ago this was a manifesto with no code. Today Busbar has its first release candidate, 1.0.0-rc.1: feature-complete and API-stable, in a single Rust binary you can run right now.

Here’s what landed.

Lossless, both ways

Six wire protocols (OpenAI, OpenAI Responses, Anthropic, Gemini, Amazon Bedrock, Cohere) native on both sides, translated through a superset intermediate representation rather than flattened to one vendor’s shape. Point a Bedrock SDK at Busbar and reach an Anthropic backend. The native features survive the hop, streaming included.

Failover inside the request

If a lane fails before your client has seen a byte, Busbar reroutes to the next lane in the pool, even mid-stream, within a configurable deadline and hop budget. Your user sees a slight pause, not an error.

A breaker that knows whose fault it is

Every provider connection has a circuit breaker that classifies failures. Transient errors cool down and probe. Hard-down failures like auth or billing get a sticky cooldown. Your own 4xx errors never penalize the lane. A context-length overflow fails over to a bigger model. It’s reliability engineering, not a retry loop.

Governance built in

Virtual keys with budgets, RPM and TPM rate limits, and pool-level access control, so you can hand a scoped, capped key to a staging environment or an internal tool without trusting every caller to self-police.

One binary

No Python sidecar, no interpreter, no GC in the request path. Download it, point your SDK at it, done.

Why “rc,” not “1.0”

It’s feature-complete and the contracts are stable, but 1.0 is a promise: frozen APIs under Semantic Versioning, hardened under real load. That’s what the release-candidate window is for. Soak, audit, and fix before I make that promise. More milestones to come.

Try it at getbusbar.com, and tell me what breaks.