> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unseen.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# Payment lifecycle

> Payment statuses, verify outcomes, and fulfillment tips for Unseen Pay sessions.

With [environments aligned](/concepts/environments), the last conceptual piece is **what happens to one session over time**. That shapes how you fulfil orders—before you memorize individual SDK calls in the next section.

## Session states

Server types mirror the REST API. Common `status` values include:

* **`pending`** — created, not yet confirmed on-chain
* **`confirmed`** — settled and verified
* **`expired`** — session TTL elapsed
* **`cancelled`** — cancelled via API (only pending sessions)

Use `unseen.payments.get(id)` or list filters to observe state from the server.

## Verification

`payments.verify(paymentId)` (server SDK) or the UI’s polling flow returns a result whose `status` can include:

* **`confirmed`**
* **`pending`**
* **`amount_mismatch`** — amount on-chain does not match the session (treat as failure / manual review)

The UI polls for a limited window after the user taps **I have paid**; if confirmation is slow, retry verify from the server or rely on webhooks.

## Fulfillment checklist

1. Treat **idempotency**: the same payment ID or reference may be observed more than once (retries, webhook + client).
2. Prefer **webhooks + verify** together: webhook for push, verify for manual recovery.
3. Store **`reference`** as your internal order or invoice key.

**Next:** [Server SDK — Installation](/sdk/server/installation) — turn these states into typed API calls.