# Lasso RPC

> Geo-distributed EVM JSON-RPC proxy with multi-provider routing, automatic failover, and strategy-based cost/latency control via URL path. Open source (AGPL-3.0).

Lasso routes every EVM RPC request across multiple providers per chain with automatic failover. Requests are routed to the fastest upstream provider in the caller's region. Three routing strategies selected via URL path — the URL is the config.

## What Lasso Improves

Replaces single-provider RPC setups (Alchemy, Infura, QuickNode, public endpoints) with multi-provider routing:
- Automatic failover — provider goes down, requests route to the next best
- Strategy control via URL — `/fastest/ethereum` vs `/load-balanced/ethereum`
- Geo-distributed — lowest-latency upstream provider in any region
- One key, all chains, all strategies
- Open source routing engine: https://github.com/jaxernst/lasso-rpc

## Access Modes

- **Pay-per-call:** `https://mpp.lasso.sh` — no keys, no accounts, pay per request via Tempo wallet
- **Agent keys:** `https://lasso.sh/api/v1/agent/keys` — persistent prepaid keys, key-in-URL format `/rpc/k/:key/:strategy/:chain`
- **Dashboard:** `https://lasso.sh` — human-managed accounts with live monitoring, custom profiles, BYOK
- **Self-hosted:** https://github.com/jaxernst/lasso-rpc (AGPL-3.0)

## Routing Strategies

| Strategy | Path | Cost (std read) | Best For |
|---|---|---|---|
| Load Balanced | `/load-balanced/:chain` | $0.0001 | Indexing, batch queries |
| Latency Weighted | `/latency-weighted/:chain` | $0.00015 | Production apps, general purpose |
| Fastest | `/fastest/:chain` | $0.0002 | Trading, MEV, time-sensitive |

Default (no strategy in path): latency-weighted.

## Domains

- `mpp.lasso.sh` — pay-per-call RPC + free discovery endpoints (pricing, chains, OpenAPI)
- `lasso.sh` — agent key management API, key-authenticated RPC, dashboard, SKILL.md

Agent key creation/funding uses `lasso.sh` endpoints. Tempo CLI handles MPP payment via 402 negotiation.

## Discovery (No Auth)

- GET https://mpp.lasso.sh/chains — available chains (do not hardcode)
- GET https://mpp.lasso.sh/pricing — per-method pricing
- GET https://lasso.sh/api/v1/agent/pricing — agent key CU pricing

## Payments via Tempo

Lasso uses the Tempo wallet for agent-automated billing. Tempo CLI handles 402 payment negotiation transparently.

- Tempo SKILL.md (wallet setup): https://tempo.xyz/SKILL.md
- Install: `curl -fsSL https://tempo.xyz/install | bash`
- Free keys (no Tempo needed): POST /api/v1/agent/keys with `{"wallet_address": "0x..."}`

## Full Reference

- Agent skill (install in your agent): https://lasso.sh/SKILL.md
- Dashboard: https://lasso.sh
- Source: https://github.com/jaxernst/lasso-rpc