---
title: About Superstables
description: What Superstables is: open-source software for agent payments using test tokens only, with owner-approved budgets or single purchases, and a free index of payable services.
canonical: https://staging-next.superstables.com/about
last-updated: 2026-10-14
---

# About Superstables

> Superstables lets AI agents pay for services from their owner's wallet, within a budget the owner approves or as a single purchase. It also runs a free index of services that accept stablecoin payments.

## Budgets and single purchases

The open-source Superstables client lets an agent that can run commands, such as Claude Code or Codex, pay for services. The owner chooses how. With a budget, the owner approves a spending limit once in their wallet, and the agent can make compatible purchases within it without asking each time. Single purchase: approve one purchase in your wallet, on your machine or on superstables.com. The owner can see and revoke budgets from their account.

Testnet only: payments use test tokens, and no real money moves.

- [Get started](https://staging-next.superstables.com/get-started): one prompt for your agent
- [Client source on GitHub](https://github.com/superstables/superstables), Apache-2.0

## What the index is

Agents increasingly pay for what they use: data feeds, GPU and compute time, tools, and other agents. Those services announce their prices over payment protocols such as x402 and MPP, on chains such as Base, Solana and Tempo, in stablecoins such as USDC, EURC and USDT. Superstables collects those announcements into one directory so an agent, or the person building one, can find a listed service and see what our last probe detected before calling it.

The index is free for humans and for agents. There is a web directory, a public JSON API with no key and CORS open, an MCP server, and a natural-language endpoint. Listing a service is free as well. There are no paid tiers and no paid placement; if that ever changes, pricing.md changes first.

## How it is built

A crawler reads public directories of payable services on a schedule, normalises chains, assets and prices, and merges entries that point at the same endpoint host. Every entry keeps a record of the sources it was found in, so provenance is never lost.

Each HTTP endpoint is then probed on a rolling schedule with a plain GET request that identifies itself as SuperstablesCrawler. The crawler also fetches providers' home pages and icons, identified the same way, and stores a copy of each icon it finds. Live means the endpoint returned HTTP 402 or a detected payment-challenge signal at its last unpaid probe. Other detected signals are the presence of a recognised payment-challenge header or an x402- or MPP-looking body. It does not establish payment compatibility, settlement, delivery or output quality. Endpoints that are not HTTP are listed but never probed, and show as Not checked. Probe history is kept and shown on every service page, and services that stop appearing in their sources are delisted after seven days.

## Neutrality

Superstables does not operate a payment rail, a facilitator, a chain or a stablecoin, and does not take a fee on anything listed. Ranking in the directory follows liveness and recency, not commercial relationships. The Index API docs describe the field contract and the breaking category change in OpenAPI document version 2.0.0.

## What the index does not do

The index lists services and probes their payment challenges; it does not pay them. A listing does not mean a service works with the Superstables client. In browser-wallet flows, the owner's private key stays in their wallet; budget agents hold separate local spending keys.

## For agents and developers

The fastest way in is the machine-readable material:

- [llms.txt](https://staging-next.superstables.com/llms.txt): the site index written for agents
- [API reference](https://staging-next.superstables.com/docs) and [OpenAPI spec](https://staging-next.superstables.com/openapi.json)
- [MCP server card](https://staging-next.superstables.com/.well-known/mcp/server-card.json)
- [Authentication](https://staging-next.superstables.com/auth.md): none required
- [Privacy](https://staging-next.superstables.com/privacy): what we store and why

## Questions and answers

### What is Superstables?

Open-source software that lets AI agents pay for services from their owner's wallet, with a budget or a single purchase the owner approves. Testnet only for now. It also runs a free index of services advertising stablecoin payments over x402 and MPP.

### Is it free?

The index is. The web directory, the JSON API, the MCP server and the natural-language endpoint need no key, no account and no payment, and listing a service is free. There is no paid placement. The client is open source. Services set their own prices, and network fees are separate.

### What does live mean?

Live means the endpoint returned HTTP 402 or a detected payment-challenge signal at its last unpaid probe. It does not establish payment compatibility, settlement, delivery or output quality. Probe history is shown on every service page.

### Does the directory execute payments?

No. It indexes and probes. It does not route, execute or settle payments and never holds funds.

### How do I get a service listed or corrected?

Submit the endpoint through the form or POST /api/v1/submit. New submissions enter the review queue and require approval before they enter the directory crawl pipeline. For a correction, contact us with the service ID and the details to change. Repeating an endpoint submission within 24 hours does not update the earlier submission. To remove a listing, contact us with the service ID.

Last updated: 2026-10-14