Technical stack, in plain English

walras is a TypeScript service on Node.js 22 or later. The HTTP surface is Fastify, exposing the x402 facilitator endpoints (verify, settle, supported) and the two Bazaar discovery endpoints (catalog listing and ranked search).

Payment verification and settlement are not reimplemented: walras wraps the Apache-2.0 @x402/stellar package, which validates Soroban authorization entries and submits the token transfer on Stellar, and adds zero payment validation of its own (docs/FACTS.md rows F-044, F-045). Network fees are sponsored by the facilitator's submitter account, so a buyer needs only the payment asset (F-006).

The discovery catalog is SQLite through Node's built-in node:sqlite module — zero added database dependencies (docs/DECISIONS.md entry D-023) — with SQLite's FTS5 full-text index and BM25 ranking behind a one-method retriever seam, so ranking can improve without touching the wire contract (D-026).

An MCP (Model Context Protocol) server exposes the whole discover-then-pay loop to agents as two tools, search_resources and paid_call, over stdio (F-080).

Version 1 ships no new Soroban smart contract: the audit surface is an off-chain service and its cryptographic validation (docs/THREAT-MODEL.md section 4).