Bifrost

Bifrost is an AI gateway that provides a unified OpenAI-compatible interface across hundreds of models and supports vendor failover and load balancing.

Bifrost is a Go LLM gateway open-sourced by Maxim AI, integrating semantic caching, model fallback chains, virtual key budgets and observability.

The open-source Go gateway Bifrost maintains 11 microseconds of routing overhead at 5000 requests per second.

Bifrost's internal concurrency pattern relies on a Go worker pool and bounded channels; when the downstream channel fills up, it stops reading the upstream HTTP response body, causing the gateway's operating system to send a TCP zero-window signal to the upstream inference provider, and the upstream inference loop stalls.

Bifrost uses a sliding token window to evaluate streaming chunks, matching incoming text in flight against regex patterns and safety classifiers; if the stream begins outputting sensitive data, the gateway short-circuits the pipeline, terminates the stream with a downstream SSE error frame, and immediately cancels the upstream provider context.

Bifrost introduces a Virtual Key mechanism, where each caller gets a Virtual Key, budgets, rate limits and model permissions are attached to the key, and hierarchical enforcement is used so that a sub-team's budget does not exceed its parent's.

Bifrost's cluster mode uses peer-to-peer nodes with no single leader, sharing traffic patterns, rate limit state and provider health information via a gossip protocol.

Bifrost has obtained SOC 2 Type II, ISO 27001, HIPAA and GDPR compliance certifications.

Bifrost Edge is an agent running on employee laptops that can route the AI traffic of desktop apps, browser AI and coding agents to the same gateway, a capability the other four of the five products compared in this article do not have.

Through a single OpenAI-compatible interface, Bifrost can access more than 10,000 models from over 25 providers, covering OpenAI, Anthropic, AWS Bedrock, Google Vertex, Azure, Gemini, Groq, Mistral, Cohere, xAI, as well as self-hosted options such as vLLM, SGLang and Ollama.

Bifrost is an open-source AI gateway built in Go, with its core under the Apache 2.0 license, and a paid enterprise edition offering identity management, high availability and support.

According to a case study published by Maxim, Bifrost's Code Mode reduced running cost from $377 to $29, a drop of about 92%, in a test spanning 16 MCP servers and 508 tools, while maintaining a 100% task pass rate.

Bifrost emphasizes high-performance proxying and low latency.

Bifrost's open-source core is licensed under Apache 2.0 and is free to self-host permanently; the enterprise edition uses custom pricing and offers a 14-day free trial.

Bifrost is an open-source gateway and control plane for production AI infrastructure, developed by Maxim AI.

Bifrost supports 10,000+ models from 25+ vendors and provides an OpenAI-compatible API, allowing existing applications to integrate by simply changing the API base URL.

Bifrost is built in Go and optimizes the request path for low overhead by keeping configurations in memory, pre-warming memory pools at startup, and maintaining persistent vendor connections.

In an official benchmark test run on AWS EC2 with 500 concurrent users over 60 seconds, Bifrost achieved 424 requests/second while LiteLLM achieved 44.84 requests/second.

In the official benchmark test, Bifrost consumed 120 MB of memory with a 100% success rate, while LiteLLM consumed 372 MB with an 88.78% success rate.

Bifrost supports MCP Gateway, in which MCP Code Mode lets models orchestrate tools via sandboxed code, reducing input tokens by up to 92.8% for large toolsets.