# Sippar

> A payment relay for the agent economy. One wallet. Any chain. Every x402 service. Sippar lets people and AI agents pay for any x402 / MPP service across many chains from a single threshold-derived wallet, secured by ICP threshold signatures, and returns a verifiable on-chain receipt for every payment. Pay by the drop.

Sippar is infrastructure for the open x402 payment standard, not a wallet app. An agent (or app, or human) holds one wallet and pays priced HTTP services across chains; Sippar signs the payment, it settles on-chain, and the receipt is the proof the payment happened. The verified catalog below is discoverable by anyone. There are three ways to pay, and only one of them needs a credential. You can buy one of Sippar's own products, which answers a real 402 and takes payment from your own wallet with no credential at all. You can use the public pay endpoint, which needs no credential but no longer pays out of Sippar's treasury for an anonymous caller (2026-08-31) and answers 402 saying so. Or you can pay any listed third-party service from your own wallet through the sovereign endpoints, which need an access token during the private beta.

## Discover services

- [Verified marketplace catalog (JSON)](https://sippar.network/api/sippar/marketplace): the live, machine-readable list of verified x402 services and the BlockRun data tools (web/research search, prediction markets, DeFi data, market/social data, blockchain RPC), each with price, chain, its request shape (see below), and (for the dynamic tools) usage and example commands.
- [Attested catalog (JSON)](https://sippar.network/api/sippar/marketplace/attested): the same commands plus the on-chain payment proof that settled each verification (`proof.txHash`, independently checkable on the x402_payments ICP canister) and the request shape.
- [Marketplace (web)](https://sippar.network/marketplace): browse verified services across chains.
- [MCP server](https://sippar.network/mcp/protocol/pay): for AI agents. Point an MCP client at that URL (Streamable HTTP). `initialize`, `tools/list` and `ping` need no credential, and neither do 13 of the 18 `tools/call` tools, including `list_products`, `buy_product`, `pay` and `discover_services`. Five need an access token: `transfer`, `session_draw`, `relay_pay`, `batch_pay` and `pay_paysh_service`. The rule is that a tool needs a credential when the caller names both whose wallet pays and who gets paid; buying a product names neither. Tools span sovereign threshold-wallet payments, MPP sessions, cross-chain relay, and agent-to-agent settlement. [https://sippar.network/mcp](https://sippar.network/mcp) is a plain directory of these addresses, not the protocol endpoint.
- [Sippar's own paid endpoints (JSON)](https://sippar.network/.well-known/x402): every product Sippar sells directly, each with its price, its exact request body, and what happens after you pay (the collect URL, the delivery guarantee, and the latency to expect). This document is enough to make a first successful call without reading any HTML.

## Social listening: buy it, do not drive the page

[https://sippar.network/social/](https://sippar.network/social/) is a human interface. An agent should not try to operate it. The same data is one paid HTTP call:

- `POST https://sippar.network/api/sippar/sell/social-search` with `{"query": "..."}`. Unpaid, it answers a real HTTP 402 carrying the price, the payee and the rails. Pay from your own wallet and retry with the header the 402 names. No account on any platform, no API key, no signup, no credential of ours.
- Same purchase by product id: `POST https://sippar.network/mcp/tools/pay/buy` with `{"productId":"social-search","input":{"query":"..."}}`, or the `buy_product` tool on the MCP endpoint above. Neither needs a credential.
- Read [the sippar-social-data skill](https://sippar.network/skills/sippar-social-data/SKILL.md) before the first call. It carries what a resource entry cannot: the call runs well over a minute so a short client timeout looks exactly like a service that ate the money, a timed-out call is collected by re-presenting the same payment rather than paid for twice, and the answer is Sippar's own cited summary plus links rather than the post bodies.
- The price and the request shape are in the catalog, never in prose: `GET https://sippar.network/mcp/tools/pay/products/social-search`.

The page offers more than the product does. It searches more platforms, takes time windows and sort options, and sells an audio brief and a deeper report out of page credit. Those are not purchasable per call yet. `social-search` is the whole of what an agent can buy today, and it covers Reddit, YouTube and LinkedIn on one question.

## How payment works

- x402 is an open standard: a priced service answers an unpaid request with HTTP 402 and its payment terms; the caller pays and retries. Sippar reads the 402, settles from your wallet using ICP threshold signatures, and returns the response plus a receipt.
- A "sip" is one small pay-per-call payment. No subscription, no account, no seed phrase.
- Settlement is same-chain per service; Sippar bridges chains so a balance on one chain can buy a service priced on another.

## For builders

- [Solana Agent Kit x402 plugin (open source)](https://github.com/Nuru-AI/sippar-sak-x402): pay x402 services from a Solana agent.
- [Ask Humans, x402-payable human answers](https://github.com/Nuru-AI/sippar-ask-humans): pay USDC on any of several chains; verified humans answer in minutes.
- [Igigi Swarm, sovereign agents paying each other (MIT)](https://github.com/Nuru-AI/igigi-swarm): agents with their own wallets settling over MPP on mainnet.
- [sippar-social-data (agent skill)](https://sippar.network/skills/sippar-social-data/SKILL.md): the skill file Sippar itself uses to buy social data per call, with the endpoints and request shapes already verified. Scripts: [listen.sh](https://sippar.network/skills/sippar-social-data/scripts/listen.sh) runs X, Reddit, YouTube and LinkedIn on one question; [comments.sh](https://sippar.network/skills/sippar-social-data/scripts/comments.sh) pulls comments on one video. Start with `--dry-run`, which prints the exact calls and the cost and spends nothing. No account or API key on any platform.

## Access

- The catalog is public. There are three ways to reach it, and only one of them needs a credential. None of them is free: you pay for what you buy.
- **Buy a Sippar product, no credential, your wallet pays**: `POST https://sippar.network/api/sippar/sell/social-search` (or any resource in `/.well-known/x402`), or `POST https://sippar.network/mcp/tools/pay/buy` with a `productId`. Unpaid, both answer with the payment terms; pay and retry. This is the path for anyone outside Sippar, and it is the one an ordinary x402 client already knows how to walk unaided.
- **No credential, but the treasury no longer pays**: `POST https://sippar.network/mcp/tools/pay/pay` still takes no credential and still answers, but since 2026-08-31 it does not spend Sippar's own money for an anonymous caller: it returns 402 saying so. Its other refusals are unchanged and still cost nothing — a host Sippar has not bought from and proven on-chain, and individual routes held back on legal grounds. Body: `{principal, serviceUrl, method, payload, maxAmountUSD, payFromChain}`. Use the product door above instead; it is the one an ordinary x402 client already walks unaided.
- **Your own wallet, any listed third-party service**: the sovereign pay endpoints need a Sippar access token during the private beta.
- Request access: elad@sippar.network

## Request shape on a catalog entry

Each catalog entry carries a `shape` object saying how to call that command, so an agent does not have to probe the service's 402 first (most payment gateways do not answer an unpaid probe):

- `inputType` (query / address / token / ticker / none), `invocation` (get / get-query / post-json), `inputExample`, `bodyTemplate` (JSON with an `{input}` placeholder), `queryParam`.
- A field is omitted when unknown, never null and never a placeholder. No `shape` object at all means no shape is recorded; `shape.inputType: "none"` means the command takes no input.
- `shape.shapeSource` says where the shape came from: `vendor-advertised` (recorded from the vendor's own 402 / openapi / docs) or `enrichment-inferred` (Sippar's inference from the URL — callable, but not a claim the vendor made).
- Request headers are never published: they can carry upstream credentials.

## Notes for crawlers and agents

- Base URL: https://sippar.network
- Public catalog endpoint: GET https://sippar.network/api/sippar/marketplace (no token required, read-only)
- Public attested endpoint: GET https://sippar.network/api/sippar/marketplace/attested (no token required, read-only) — adds the on-chain proof per command
- Public pay endpoint: POST https://sippar.network/mcp/tools/pay/pay (no token required). Attested hosts only and rate limited per caller, but since 2026-08-31 Sippar's treasury does not fund anonymous callers here — it answers 402. To buy something, use the product door: POST https://sippar.network/mcp/tools/pay/buy.
- The brokered tier (services Sippar fronts on your behalf) is not listed here and remains private.