Capability · Comparison
LiteLLM vs OpenRouter
LiteLLM and OpenRouter both solve 'one API for many models', but in very different ways. LiteLLM is a Python library (and optional proxy server) that translates between provider SDKs — it's code you run. OpenRouter is a hosted service with a single API key that routes to hundreds of models; you never touch the individual provider APIs. Often they're complementary: LiteLLM talks to OpenRouter.
Side-by-side
| Criterion | LiteLLM | OpenRouter |
|---|---|---|
| Form factor | Python lib + optional proxy (self-hosted) | Hosted SaaS API |
| Accounts required | One per provider | Just OpenRouter |
| License / source | MIT (open source) | Proprietary service (client libs open) |
| Model coverage | 100+ providers via adapters | 200+ model endpoints |
| Fallback / retry policies | Yes — configurable in proxy | Yes — built-in auto-routing |
| Budget controls / virtual keys | Yes (proxy mode) | Yes — per-key spend limits |
| Price markup | Zero — you pay providers directly | ~5% markup over provider pricing |
| Data plane ownership | You (self-host) | OpenRouter (hosted) |
| Enterprise features | SSO, audit logs in enterprise tier | Team accounts, sub-keys |
Verdict
LiteLLM is the pick when you want control, data-plane ownership, and no per-token markup — you run the proxy yourself and connect to each provider with their keys. OpenRouter is the pick when you want maximum simplicity: one key, one bill, 200+ models reachable. The two compose beautifully: run LiteLLM Proxy as your internal gateway with auth / budgets / logging, and point it at OpenRouter as one of its providers. That gives you developer simplicity in front and provider-direct cost optimisation behind.
When to choose each
Choose LiteLLM if…
- You want to self-host your LLM gateway.
- Data-plane ownership or no-markup pricing matters.
- You need fine-grained logging, budgeting, and key management in your infra.
- You want an open-source tool you can audit and extend.
Choose OpenRouter if…
- You want the simplest possible multi-model setup.
- You want to evaluate dozens of models without signing up for each provider.
- A small markup is fine in exchange for zero ops.
- You're building quickly and haven't standardized on providers yet.
Frequently asked questions
Can I use LiteLLM with OpenRouter?
Yes — that's one of LiteLLM's most common patterns. Set up LiteLLM Proxy with OpenRouter as a provider (among others). You get LiteLLM's gateway features plus OpenRouter's model breadth in one layer.
Does OpenRouter support streaming and function calling?
Yes, for models that support them. OpenRouter normalizes most request/response shapes to OpenAI format, but each model's capability set is what it is — function calling on Llama-3.3 is weaker than on GPT-5.
How do budget controls compare?
LiteLLM Proxy has rich per-virtual-key budgets, rate limits, and team tags. OpenRouter has per-key spend caps. For fine-grained internal cost attribution, LiteLLM is stronger; for simpler needs, OpenRouter is fine.
Sources
- LiteLLM — Docs — accessed 2026-04-20
- OpenRouter — Docs — accessed 2026-04-20