Documentation

A decentralized exchange for LLM inference. Sellers compete on price, buyers get the cheapest rate, and everything settles on-chain via USDC on Base.

Quickstart API Reference

What is this?

Surplus Intelligence is a two-sided marketplace for AI inference. Think of it as a stock exchange, but for API calls to AI models.

Buyers get one API key and one base URL. Call it like OpenAI — the marketplace routes to the cheapest available seller.
Sellers list any OpenAI-compatible endpoint, set their own price, and get paid in USDC per request.
Settlement is on-chain on Base — transparent, non-custodial, and verifiable by anyone.

Choose your path

Buyer Quickstart

Sign in, get an API key, and make your first request in 2 minutes — works with Cursor, Aider, and any OpenAI-compatible tool.

Seller Quickstart

List your API endpoint, set your own prices, and earn USDC per request.

Agent Quickstart

Build autonomous agents that pay per-request via x402 or MPP — no account needed.

Claude Code (Anthropic Skin)

Point Claude Code or the Anthropic SDK at the marketplace — on any model, not just Claude.

Cursor Setup

Point Cursor at the marketplace with one base-URL change.

OpenCode / Aider

Use the marketplace from OpenCode, Aider, and other CLI coding tools.

BYOK Priority Provider

Bring your own provider key and have your requests routed to it first.

Wallet Funding

Fund your wallet with USDC on Base — on-chain, by card, or with credits.

API Reference

Full endpoint documentation for the OpenAI-compatible surface and the marketplace APIs.

Security & Privacy

Seller key handling, logging, deletion, limits, and current trust assumptions.

Payments

The four settlement rails: USDC on-chain, x402, MPP (Tempo), and fiat.

Changelog

What changed in the marketplace and the API surface.

Current snapshot

These numbers change as the live model registry and seller order book change. Treat the APIs as the source of truth.

GET /v1/models returned 145 catalog models in a recent live snapshot, including text, vision, image, audio/music, video, TTS/STT, and embedding models.
The public Market Prices page returned 76 active marketplace models in that snapshot, including active image and music/audio listings. Counts change with seller liquidity; query the live endpoints for current numbers.
GET /v1/prices tracks pricing data across 10 provider pricing sources.
The seller allowlist contains 11 provider domains; active production marketplace offers are currently concentrated on Venice and Bankr LLM Gateway.
On-chain settlement — USDC on Base, current fee multiplier 10000 (1.0x / no percentage markup).
OpenAI-compatible — works with Cursor, Aider, OpenCode, Continue, and any tool that speaks /v1/chat/completions.
Anthropic-compatible — an "Anthropic skin" at /anthropic lets Claude Code and the Anthropic SDK route through the marketplace (on any model, not just Claude).
Three payment rails — API key (traditional), x402 (USDC micropayments), MPP (Tempo).

Canonical base URL: https://api.surplusintelligence.ai/v1