# Data delivery methods

> REST pull or webhook push: how each delivers data, and when to use which.

Vestiarion gives you its data in two ways. You pull it with the REST API when you need it, or Vestiarion pushes each new ledger entry to you with a webhook. Most integrations that follow the ledger use both.

## Compared

| | REST API (pull) | Webhooks (push) |
| --- | --- | --- |
| What you get | Any resource: status, the ledger, invoices, counterparties, milestones, the treasury and insights | Each new ledger entry, as a `ledger.appended` event |
| Who starts it | You send a `GET` request | Vestiarion sends a `POST` to your HTTPS endpoint |
| Latency | Data is read live on each request, so it is as fresh as your last request | Right after the request or the agent tick that appended the entry. A failed delivery is [retried](https://www.vestiarion.xyz/docs/webhooks/retries) with backoff; see [Timing](https://www.vestiarion.xyz/docs/webhooks#timing) |
| Authentication | A [workspace API key](https://www.vestiarion.xyz/docs/get-started/authentication) in `Authorization: Bearer` | You [verify](https://www.vestiarion.xyz/docs/webhooks/verify) the `Vestiarion-Signature` header with the endpoint's secret |
| Ordering | The ledger is ascending by `seq`; the other collections are newest first | Not in order: sort by `entry.seq` |
| Duplicates | Paging with the cursor never repeats a row, and a stored ledger cursor never goes back before its position | [At least once](https://www.vestiarion.xyz/docs/webhooks/guarantees): de-duplicate on the event id |
| Setup | An owner or admin creates a key in Settings | An owner or admin adds an endpoint in Settings, up to 5 per workspace |
| Use it when | You need the books, counterparties, the treasury or insights; you backfill history; you cannot receive inbound HTTPS | You want to act on each decision as it is recorded, without polling |

## Using both

To follow the ledger without missing an entry:

1. Backfill with [`GET /api/v1/ledger`](https://www.vestiarion.xyz/docs/api/list-ledger-entries), paging with the cursor until `hasMore` is `false`. Store the last non-null `nextCursor`.
2. Receive new entries by [webhook](https://www.vestiarion.xyz/docs/webhooks), and store each one keyed by its `seq`, so a duplicate or an out-of-order delivery lands in the right place.
3. Now and then, resume the ledger from your stored cursor. It returns anything a webhook did not bring, such as an entry whose delivery [failed for good](https://www.vestiarion.xyz/docs/webhooks/retries).

## No WebSocket

Vestiarion has no WebSocket or streaming endpoint: webhooks already push each ledger entry as it is appended.