If you want a hard daily spend cap and a per-request cost ledger on one machine with no database server to run, RelayPlane is the smallest install of the three (@relayplane/proxy on npm, free, MIT). If you want 100+ providers behind one gateway for a team, LiteLLM is the better tool. If you want a hosted API you don't run yourself, OpenRouter is the better tool. All three are real, none of them is a straight replacement for the other two, and this piece is an honest breakdown of where each one actually wins.
I built RelayPlane, so I'm biased. Every RelayPlane line below matches its code or docs, and the LiteLLM and OpenRouter lines come from their own docs, linked under the table, so you can check them yourself.
What each one is, in one line
-
RelayPlane: a local proxy that meters every request on the machine it runs on, enforces a hard spend cap before the request leaves, and has a kill switch. No Docker, no Python, runs on
localhost:4100. - LiteLLM: an open source AI gateway for a team, deployed as a service with virtual keys, per-tenant budgets, and 100+ providers behind one OpenAI-format API.
- OpenRouter: a hosted API that gives you one key and one endpoint for 500+ models across many providers, no infrastructure to run, billed through their platform.
The comparison
| RelayPlane | LiteLLM | OpenRouter | |
|---|---|---|---|
| What it is | Local proxy for one machine | Self-hosted gateway for a team | Hosted model marketplace |
| Install | npm install -g @relayplane/proxy |
pip install or uv, run the proxy |
No install, API key only |
| Runs locally | Yes | Yes (self-hosted) | No, cloud only |
| Native providers | 6 (Anthropic, OpenAI, Gemini, xAI, Ollama, and OpenRouter passthrough) | 100+ | 500+ (it IS the aggregator) |
| Per-request cost ledger on your machine | Yes, a local SQLite file, nothing to deploy | Spend logs live in the proxy's database | Dashboard on their cloud |
| Hard daily spend cap enforced before the request leaves | Yes (relayplane cap set --day 50, returns 429) |
Budgets per virtual key, team, user | Per-key credit limits, enforced in their cloud |
| Kill switch | Yes, one command, survives a restart | Block a virtual key via the admin API | Disable the key in their dashboard |
| Routing by task complexity | Yes, one config field, hot reloads | Router strategies you configure per deployment | No, you pick the model per call |
| Virtual keys / multi-tenant budgets | No | Yes, this is its core job | Per-key limits, cloud side |
| Self-hosted | Yes | Yes | No |
| Where your data lives | Your machine only | Wherever you deploy it | Their servers |
| License / model | MIT, everything free | MIT + enterprise license and hosted option | Proprietary, 5.5% fee on credit purchases |
The LiteLLM column comes from github.com/BerriAI/litellm and docs.litellm.ai, the OpenRouter column from openrouter.ai/docs, and the RelayPlane column from github.com/RelayPlane/proxy and relayplane.com/docs.
Where LiteLLM wins outright
Provider breadth and the multi-tenant model. If you're running a platform team with multiple apps and want virtual keys, per-team budgets, load balancing across many deployments, and an admin dashboard for the whole org, that's what LiteLLM is built for. RelayPlane has none of that, it tracks one machine, not a tenant hierarchy.
Where OpenRouter wins outright
Zero infrastructure. You get an API key and you're calling 500+ models in one format, with nothing to run or maintain. The tradeoff is you don't get a local, offline-readable cost ledger or a hard cap enforced before the request leaves your machine, you're working from their dashboard and their usage API.
Where RelayPlane's narrow wedge is
Three things. I use all of them daily on a pipeline that routes real production traffic.
-
A per-request ledger with no database server to run. Every request through
localhost:4100gets priced and written to a local SQLite file with model, tokens, cost, agent, and session.relayplane kills --last 7dshows every blocked request with the agent and session that caused it. -
A hard cap the proxy enforces, not a report you read after the bill arrives.
relayplane cap set --day 50returns429 budget_exceededon the request that would cross $50. Choose block, downgrade to a cheaper model, or warn. -
A kill switch that survives a restart.
relayplane killreturns503 kill_switch_activeon every routed request untilrelayplane resume.
You don't need a database server or an account for any of it. It's a single npm install.
The honest answer to "which one should I use"
- Pick RelayPlane if you're solo or on one machine and want to see and cap what you're spending without standing up infrastructure.
- Pick LiteLLM if you run a platform team with several apps and users, and budgets that need enforcing per tenant.
- Pick OpenRouter if you don't want to run anything and just need one key for a lot of models.
- If you want OpenRouter's model catalog and a hard local cap, point RelayPlane at OpenRouter as its upstream. RelayPlane keeps the ledger and the kill switch, and OpenRouter supplies the models.
Try it
npm install -g @relayplane/proxy
relayplane init
relayplane start
export ANTHROPIC_BASE_URL=http://localhost:4100
That's the whole setup. Source is at github.com/RelayPlane/proxy, MIT licensed, free, no paid tier.
Top comments (1)
The deployment boundary is the real differentiator here. A local ledger plus a preflight cap makes spend control auditable before a request leaves the machine, while LiteLLM still fits teams that need tenant budgets. The OpenRouter plus local cap combination is a useful middle path for teams that want breadth without giving up guardrails.