OpenRouter alternatives: AI gateways and model routers
OpenRouter alternatives ranked by AgentReady score, with LiteLLM leading at 84 and OpenRouter close behind at 81.
LiteLLM is the top-scoring OpenRouter alternative in the StackResolve registry, at 84 AgentReady versus OpenRouter's 81. Both are strong. The gap comes almost entirely from operability: LiteLLM scores 82, OpenRouter 44. If you want one gateway that fronts many model providers behind one API, these two lead a short field of five that we score in the model-routing category.
#How we score a gateway
AgentReady is one 0 to 100 number built from four parts: discovery (can an agent find it), understanding (are the docs and API legible to a machine), adoption (how quickly an agent can wire it in), and operability (does it hold up in production with logs, retries, and error surfaces an agent can read). A router can nail discovery and docs and still lose points if its runtime behavior is hard for an agent to reason about.
#The five we score
Numbers below are live from the registry as of 2026-08-25.
| Tool | AgentReady | Discovery | Understanding | Adoption | Operability |
|---|---|---|---|---|---|
| LiteLLM | 84 | 80 | 92 | 80 | 82 |
| OpenRouter | 81 | 100 | 92 | 88 | 44 |
| Helicone | 63 | 93 | 38 | 55 | 65 |
| Portkey | 63 | 93 | 38 | 80 | 39 |
| Unify | 50 | 87 | 23 | 43 | 47 |
LiteLLM (84). The most balanced of the group. No single part drops below 80, and understanding hits 92. That even profile is why it takes the top spot. If you self-host and want an agent to add a provider without hand-holding, LiteLLM reads cleanly.
OpenRouter (81). The easiest to find, with a discovery score of 100 and adoption of 88. One key, one endpoint, hundreds of models. Its 44 operability score reflects thinner production signals for an agent to act on, such as consistent error shapes and observability. For fast prototyping it is hard to beat.
Helicone (63). More of a gateway plus observability layer than a pure router. Discovery is high at 93, but understanding sits at 38, so an agent works harder to map the API surface. Pick it when you want logging and caching in front of your calls.
Portkey (63). Ties Helicone overall but splits the difference differently: adoption is high at 80, operability low at 39. It offers routing, fallbacks, and guardrails. An agent can adopt it quickly, then hits friction reasoning about runtime state.
Unify (50). The routing idea is interesting: send each prompt to whichever model wins on cost or latency. Understanding scores 23, the lowest here, so today an agent needs more scaffolding to use it well.
#Gateways route models; StackResolve routes capabilities
Every tool above answers the same question: given a model name, which provider serves it. That still leaves the agent choosing which tool to call for a task. StackResolve works one level up. An agent asks for a capability, such as "scrape this page" or "search these docs," and gets back the right registered tool plus a typed interface it can call. Model routing picks the brain. Capability routing picks the hands. You can run both: an agent uses a gateway for model calls and StackResolve to resolve everything else it needs to touch.
#Picking one
Want breadth and speed today: OpenRouter. Want a balanced, self-hostable gateway an agent can extend: LiteLLM. Want logging or guardrails bundled in: Helicone or Portkey. Check each tool's full profile in the registry before you commit, since scores move as vendors ship docs and fix their runtime surfaces.