# Paysell Merchant API

> Paysell is a crypto payment processor for TON and USDT on the TON network. A shop opens an invoice over a small REST API, sends the buyer to a hosted payment page, and receives a signed webhook once the transfer is confirmed on chain and credited. The fee is 0.2% of what actually arrives. Keys are live from the start — there is no separate test environment — and refunds are handled through support rather than an endpoint.

The five things that decide whether an integration works:

- Base URL `https://paysell.me/api/merchant/v1`; authentication is `Authorization: Bearer sk_live_…`, server-side only.
- Amounts you send are **decimal strings in the coin's normal units** (`"1.5"`), never JSON numbers and never smallest units. Amounts inside webhooks go the other way: integers in the smallest unit, as strings.
- The shop is derived from the API key. No request ever carries a shop id.
- Idempotency is a **body field**, `idempotency_key` — the `Idempotency-Key` header is not read.
- Release the goods only when an invoice reads `paid` or `overpaid`, never on a webhook merely arriving.

## Docs

- [Merchant documentation](https://paysell.me/docs): the whole API for a human — quick start, invoices, webhooks, statuses, limits, errors, checkout, go-live checklist.
- [Full documentation as one markdown file](https://paysell.me/llms-full.txt): everything above in a single file, written to be pasted into an LLM's context.

## OpenAPI

- [OpenAPI 3.1 specification](https://paysell.me/openapi.json): machine-readable description of every endpoint and both webhook events, generated from the running application's own models.

## Webhooks

- [Webhook reference](https://paysell.me/docs#webhooks): the two events (`payment.credited`, `payment.rejected`), the headers, the signed string, the retry schedule and the rules a webhook URL must satisfy.
- [Verified handler, end to end](https://paysell.me/docs#handler): a complete Node.js and Python receiver with signature verification and deduplication by `event_id`.
- [Common integration mistakes](https://paysell.me/docs#mistakes): the four that account for most failed integrations.

## Solutions

- [What Paysell is used for](https://paysell.me/solutions): the business cases the product is built around.

## Legal

- [All legal documents](https://paysell.me/legal): agreements, compliance and policies in one index.
- [Terms of Service](https://paysell.me/legal/terms-of-service): the master agreement between Paysell and a merchant.
- [API and Developer Terms](https://paysell.me/legal/api-terms): rules for API keys, rate limits and webhook security.
- [Fee Schedule and Limits](https://paysell.me/legal/fee-schedule): the single source of truth for every number.
- [Privacy Policy](https://paysell.me/legal/privacy-policy): what personal data is processed and why.
- [Refund Policy](https://paysell.me/legal/refund-policy): how a refund is requested and processed.

## Blog

- [Paysell blog](https://paysell.me/blog): product and payments notes.