RoundWatch MCP server

RoundWatch

Durable Algorand USDC payment monitoring for autonomous x402 workflows.

Website · Quickstart · Technical guide · Live API · OpenAPI · llms.txt · MCP Registry · Architecture

RoundWatch watches one exact future Algorand MainNet USDC payment when no transaction ID exists yet. A caller defines the expected payment, pays a one-time x402 service fee, receives a durable watch ID, and can exit. RoundWatch persists the obligation and scan progress, then exposes verified on-chain evidence for later retrieval.

Production: Algorand MainNet · Circle USDC · x402 v2 · GoPlausible facilitator · Bazaar cataloged · remote MCP endpoint · durable restart recovery.

What it solves

A short-lived agent, job, or service may need to know whether a particular payment arrives after the caller has stopped running. Keeping that caller alive to poll an Algorand Indexer is unnecessary if a durable observer can own the wait instead.

RoundWatch lets a caller define the expected payment, purchase one watch through x402, and exit. The service persists the obligation, continues scanning Algorand, and records the matching transaction for later retrieval.

A backend that already operates durable Indexer or subscriber infrastructure may reasonably implement this itself. RoundWatch is for callers that do not want to own that operational component.

Lifecycle

1. The client submits the exact expected sender, receiver, atomic amount, and optional invoice note.
2. x402 returns payment requirements and the client signs the service payment locally.
3. GoPlausible verifies and settles the service payment.
4. RoundWatch activates the persisted watch only after the exact service-payment transaction is confirmed; that transaction's confirmed round becomes the scan baseline.
5. The caller may exit while RoundWatch polls the Algorand Indexer.
6. The watch becomes matched when an exact future USDC asset transfer appears.
7. The caller reads the durable result with GET /v1/watch/:id.

See Architecture for the normal, recovery, and matching paths.

See Roadmap for the current product direction and prioritization.

Live production service

Shortened. The full README is on GitHub.