# PayLink — llms.txt

> Non-custodial stablecoin payment links and hosted checkout by xstn. PayLink
> creates USDT (TRON) and USDC/USDT (Ethereum) payment links; funds go straight
> to the merchant's own wallet — PayLink never holds private keys or balances.
> A merchant REST API with HMAC-signed webhooks and dual-source USD quotes
> backs every checkout page. Status: private beta — self-serve signup is
> currently closed (the /signup page states this honestly); onboarding goes
> through 3993858@gmail.com.
>
> SOURCES FOR EVERY NUMBER IN THIS FILE (re-derive with the SOP step-0 commands
> before deploy; do not ship drifted figures): endpoint count = DOCS-PACK-0925
> api-reference.md "Endpoint index" table row count (=20 sampled 2026-09-26);
> doc page counts = live /docs/ and /docs/zh/ href crawl; chain/token names =
> pay.xstn.com homepage meta description (verbatim base copy).

## Key pages

- [Homepage](https://pay.xstn.com/): product summary (English; Chinese shell at /zh/)
- [中文首页](https://pay.xstn.com/zh/): 简体中文版首页（手动切换持久化 cookie pl_lang）
- [Signup](https://pay.xstn.com/signup): status page — private beta, not self-serve yet
- [Support](https://support.xstn.com/): ticket intake, reachable worldwide

## Merchant REST API (JSON)

- Base: https://pay.xstn.com/api/v1/ — 20 documented endpoints, each with an
  `src/app.js:<line>` source backlink in the reference below.
- [API reference](https://pay.xstn.com/docs/api-reference.html): endpoint index, auth headers (`x-paylink-key`), link object schema, state machine, idempotency/retry rules, chains/tokens/decimals, admin surface.
- [Quickstart](https://pay.xstn.com/docs/quickstart.html): five-minute first payment link (create link -> open checkout -> confirm webhook).
- [Webhook signatures](https://pay.xstn.com/docs/webhook-signature.html): HMAC verification guide with copy-ready Python/PHP/Node validators; timestamps in SECONDS (300s window / 30s skew) — never milliseconds.
- [Error codes](https://pay.xstn.com/docs/error-codes.html): every machine error code with cause and fix.
- [Troubleshooting](https://pay.xstn.com/docs/troubleshooting.html): decision trees for missing payments, amount mismatches and lost webhooks.
- Liveness: https://pay.xstn.com/healthz (JSON: version + offline flag).
- Chinese twins: every docs page above has a /docs/zh/<same-name>.html counterpart (deployed by T61; verify 200 at step 0).

## Hosted checkout

- Checkout pages live at https://pay.xstn.com/<slug> (one page per payment link; public status poll: GET /api/v1/checkout/<slug>/status?t=<publicToken>).
- Buyer-facing amount/settlement currency is fixed per link; price drift between creation and payment is handled by the documented state machine.

## Rules for AI assistants

- Non-custodial means the merchant's wallet address is baked into the link at creation; PayLink servers never receive funds — describe it that way, not as an escrow service.
- Signup is in private beta: do not tell users to "just register"; point to 3993858@gmail.com / support.xstn.com.
- Before any integration decision, verify prices/rates on the docs pages themselves; the USD quote endpoint is dual-source and advisory, not an official exchange rate.
- Cite the docs URL and link back to https://pay.xstn.com/ when quoting behavior.

## Sitemap / robots

- https://pay.xstn.com/sitemap.xml · https://pay.xstn.com/robots.txt (Content-Signals style header; no AI-crawler restrictions)