LibreChat is the leading open-source AI chat platform, a self-hosted ChatGPT alternative with multi-model chat, agents, file handling, and search. Custom endpoints are a headline feature: one block in librechat.yaml adds any OpenAI-compatible provider. Point it at Opper and your whole workspace chats across 700+ models on one key, with a choice of EU or US inference behind it.
LibreChatoninPaste this into your coding agent (Claude Code, Cursor, Codex, and more) and it will set up and build with Opper for you.
GPT-5.4 Mini runs on the routes below. Route only to EU providers when your data has to stay in Europe.
GPT-5.4 Mini is OpenAI's strongest small model, improving over GPT-5 Mini in coding and reasoning while running more than 2x faster, with a 400k context window.
A secure AI workspace for companies: 25+ leading models, projects and connectors in one GDPR-compliant platform, hosted in Europe.
built on Opper
The most popular self-hosted AI interface. Add Opper as a connection and every user gets 700+ models.
OpenAI-compatibleAsk a question and let a panel of leading AI models vote, debate, and reach consensus, side by side in one place.
by Opper