Founder of Grafbase here.

Here are a few key differentiators vs LiteLLM today:

- Nexus does MCP server aggregation and LLM routing - LiteLLM only does LLM routing

- The Nexus router is a standalone binary that can run with minimal TOML configuration and optionally Redis - LiteLLM is a whole package with dashboard, database etc.

- Nexus is written in Rust - LiteLLM is written in Python

That said, LiteLLM is an impressive project, but we're just getting started with Nexus so stay tuned for a steady barrage of feature launches the coming months:)

What's the difference between "MCP Server Aggregation" and the litellm_proxy endpoint described here?

https://docs.litellm.ai/docs/mcp

The main difference is that while you can get Nexus to list all tools, by default the LLM accesses tools by semantic search — Nexus returns only the relevant tools for the what the LLM is trying to accomplish. Also, Nexus speaks MCP to the LLM, it doesn't translate like litellm_proxy seems to do (I wasn't familiar with it previously).

There is also https://github.com/maximhq/bifrost which apparently overcomes some performance issues of litellm and is easy to get going.

Yeah they definitely belong in the same space. Nexus is an LLM Gateway, but early on, the focus has been on MCP: aggregation, authentication, and a smart approach to tool selection. There is that paper, and a lot of anecdotal evidence, pointing to LLMs not coping well with a selection of tools that is too large: https://arxiv.org/html/2411.09613v1

So Nexus takes a tool search based approach to solving that, among other cool things.

Disclaimer: I don't work on Nexus directly, but I do work at Grafbase.