FetchMux

One search endpoint for AI agents. Put a router in front of Brave, Tavily, Exa, Firecrawl, and
Crossref. Every request carries a hard cost ceiling and deadline; every response comes back with a
receipt that says which provider ran, why, and what it cost.
Your agents stop hard-coding a provider into prompts and app code. They send one request shape; the
gateway picks an eligible provider under a policy you control, enforces the budget and deadline
before the call, retries safely on failure, and returns normalized results plus a full trace. You
keep your provider keys β they never leave your gateway.
The receipt
Nothing is a black box. Every /v1/search response carries the routing decision:
"route": {
"selectedProvider": "brave",
"attemptedProviders": ["brave"],
"reasonCodes": ["TASK_MATCH", "WITHIN_BUDGET", "RELIABILITY_WEIGHT"],
"attempts": [
{ "provider": "brave", "outcome": "success", "latencyMs": 640, "estimatedCostUsd": 0.005 }
],
"estimatedCostUsd": 0.005,
"latencyMs": 640,
"fallbackUsed": false,
"traceId": "rt_b400e7c8"
}
How it routes
agent βββΆ { query Β· task Β· maxCostUsd Β· maxLatencyMs }
β
βΌ
ββββββββββββββββ your keys
β FetchMux β ββββββΆ Brave Β· Tavily Β· Exa
β policy β Firecrawl Β· Crossref
ββββββββββββββββ ββββββ (bring your own)
β
βΌ
agent βββ evidence[] + route receipt
A provider is eligible only when its credentials, task fit, circuit state, spend, and deadline all
pass. Budgets and deadlines are eligibility rules, not best-effort hints. Fallback happens only on
retryable failures.
Quick start
No provider account needed β the public Crossref route runs out of the box:
git clone https://github.com/krutftw/fetchmux
cd fetchmux
npm install
npm run build
export FETCHMUX_API_KEY="a-long-random-key"
export CROSSREF_ENABLED=true
export CROSSREF_CONTACT_EMAIL="you@example.com"
npm run dev:gateway
From another shell:
curl http://127.0.0.1:8787/v1/search \
-H "Authorization: Bearer a-long-random-key" \
-H "Content-Type: application/json" \
-d '{ "query": "retrieval augmented generation", "task": "scholarly", "maxLatencyMs": 8000 }'
To route real web search, set a provider key and use a web task instead:
export FETCHMUX_API_KEY="a-long-random-key"
export BRAVE_API_KEY="your-brave-key"
export BRAVE_COST_PER_REQUEST_USD="0.005"
npm run dev:gateway
New to Firecrawl? New accounts get 10% off the first month through
this link (referral β FetchMux earns a small
commission, no extra cost to you).
Use it from an agent
Point any MCP client (Claude, Cursor, and friends) at the published server:
{
"mcpServers": {
"fetchmux": {
"command": "npx",
"args": ["-y", "@fetchmux/mcp"],
"env": {
"FETCHMUX_BASE_URL": "http://127.0.0.1:8787/",
"FETCHMUX_API_KEY": "your-gateway-key"
}
}
}
}
Two read-only tools: search_web and preview_search_route.
Or use the typed SDK, @fetchmux/sdk:
import { FetchMux } from "@fetchmux/sdk";
const client = new FetchMux({
baseUrl: "http://127.0.0.1:8787/",
apiKey: process.env.FETCHMUX_API_KEY,
fetch: globalThis.fetch.bind(globalThis),
});
const res = await client.search({
query: "latest stable Node.js release",
task: "fresh_facts",
maxCostUsd: 0.02,
});
Providers
Bring your own key for each. Set the matching *_API_KEY, plus an optional
*_COST_PER_REQUEST_USD if you want dollar budgets enforced.
| Provider | Use | Key |
|---|
| Brave | web search | BRAVE_API_KEY |
| Tavily | web search, research | TAVILY_API_KEY |
| Exa | web search, docs | EXA_API_KEY |
| Firecrawl | page content | FIRECRAWL_API_KEY |
| Crossref | scholarly metadata | none (CROSSREF_ENABLED=true) |
REST endpoints
| Method | Path | Auth | Behavior |
|---|
GET | /health | public | Process health and version |
GET | /ready | public | Provider readiness |
GET | /v1/providers | bearer | Provider configuration status |
POST | /v1/route/preview | bearer | Ranked candidates, no provider call |
POST | /v1/search | bearer | Routed retrieval and route receipt |
Full contract: docs/openapi.yaml.
All configuration variables
The process does not auto-load .env in local Node development; set variables in the shell or a
process manager. Docker Compose reads the ignored .env file.
| Variable | Default | Purpose |
|---|
FETCHMUX_API_KEY | none | Protected-route bearer key |
FETCHMUX_API_KEYS | none | Comma-separated keys for rotation |
FETCHMUX_AUTH_DISABLED | false | Exact true bypasses auth (trusted local use only) |
FETCHMUX_ALLOWED_ORIGINS | none | Comma-separated browser origins; no CORS when empty |
FETCHMUX_HOST | 127.0.0.1 | Bind address |
FETCHMUX_PORT | 8787 | TCP port |
BRAVE_API_KEY / TAVILY_API_KEY / EXA_API_KEY / FIRECRAWL_API_KEY | none | Provider credentials |
CROSSREF_ENABLED | false | Exact true enables the credential-free scholarly route |
CROSSREF_CONTACT_EMAIL | none | Monitored contact for Crossref's polite pool |
*_COST_PER_REQUEST_USD | none | Per-provider cost estimates used by dollar budgets |
See provider configuration before enabling maxCostUsd.
Run in Docker
cp .env.example .env
docker compose up --build -d
curl http://127.0.0.1:8787/health
Non-root Distroless image: Linux capabilities dropped, read-only root filesystem, provider
credentials passed only at container start.
Benchmark
Validate every case and provider pairing with no network calls or credits:
npm run benchmark -- --workload benchmarks/workloads/founding-v1.json --mode dry-run
Live mode needs provider keys and an explicit --confirm-live. Check each provider's terms before
publishing results β see the benchmark methodology.
What it is (and isn't)
Open source, self-hosted, single-tenant, BYOK. Route events go to stdout as JSON and exclude your
query text, keys, and result content by default. No database, no telemetry.
It is not a hosted service, a pooled-credit reseller, or a claim that these providers are
interchangeable. Provider names are the adapters it ships with, not partnerships. A hosted version
is on the roadmap β star the repo to follow.
Development
npm test
npm run typecheck
npm run lint
npm run build
npm run dev:gateway
npm run dev:site
More docs: product design Β·
local development Β·
deployment Β·
provider configuration Β·
data handling Β·
incident response
Security issues: security@fetchmux.com.
License
Apache-2.0. Free to self-host, modify, and redistribute.