# Sync data from an API

Pre-requisite: creation of an integration and at least one connection.

## Activate a sync template

Terapi uses [syncs](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api) to read data from APIs continuously. For common use cases, [templates](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api) are available to let you get started fast.

Select your integration in the *Integrations* tab, and navigate to the *Endpoints* tab. Available sync templates will appear in the endpoint list. Select the relevant one and enable it with the toggle.

Terapi will automatically sync the corresponding [records](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api) in the background for each relevant connection.

Is there no template for your API? Or none matching your exact use case?

Learn more about how to [build a custom integration](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api), [extend a template](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api) or [request custom integrations from Terapi experts](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api).

## Listen for webhooks from Terapi

Terapi sends [webhook](https://terapi.gitbook.io/terapi-api-explorer/integrate/guides/sync-data-from-an-api) notifications to your backend whenever new data is available for a connection & sync combination.

To set this up, go to the *Environment Settings* tab and configure a *Webhook URL* to which Terapi will send notifications.

The webhook from Terapi is a POST request with the following body:

```json
,
    "syncType": "INITIAL" | "INCREMENTAL",
    "modifiedAfter": ""
}
```

Webhooks with non-2xx responses are retried with exponential backoff.

Before using webhooks in production, verify their origin.

## Fetch the latest data

After receiving a Terapi webhook, fetch the latest records using the backend SDK or API:

```bash
curl -G https://api.terapi.dev/records \
  --header 'Authorization: Bearer ' \
  --header 'Provider-Config-Key: ' \
  --header 'Connection-Id: ' \
  --data-urlencode 'model=' \
  --data-urlencode 'modified_after=' \

```

```ts
import   from '@terapihq/node';

const terapi = new Terapi();

const result = await terapi.listRecords();
```

This returns an array of records conforming to the specified data model.

Each record contains useful metadata automatically generated by Terapi:

```json

            },
            ...
        ],
    next_cursor: "Y3JlYXRlZF9hdF4yMDIzLTExLTE3VDExOjQ3OjE0LjQ0NyswMjowMHxpZF4xYTE2MTYwMS0yMzk5LTQ4MzYtYWFiMi1mNjk1ZWI2YTZhYzI"
}
```

#### Cursor-based synchronization

In practice, webhook notifications can be missed, and relying solely on the webhook payload to fetch modified records can cause you to miss some updates.

A more reliable way of keeping track of how far you've synced records (for each connection & sync combination) is to rely on record **cursors**.

Each record comes with a synchronization cursor in `_terapi_metadata.cursor`. Terapi uses cursors internally to keep a chronological list of record modifications.

Each time you fetch records, you should store the `cursor` of the last record you fetched to remember how far you've synced (for each connection & sync combination).

The next time you fetch records, pass in the cursor of the last-fetched record to only receive records modified after that record:

```bash
curl -G https://api.terapi.dev/records \
  --header 'Authorization: Bearer ' \
  --header 'Provider-Config-Key: ' \
  --header 'Connection-Id: ' \
  --data-urlencode 'model=' \
  --data-urlencode 'cursor=' \

```

```ts
import   from '@terapihq/node';

const terapi = new Terapi();

const result = await terapi.listRecords();
```

So, the overall logic for cursor-based synchronization should be:

1. Receive a webhook notification from Terapi.
2. Query your database for the cursor of the last-fetched record.
3. Fetch the modified records (passing the cursor).
4. Store the modified records.
5. Store the last-fetched record cursor.

## Write back to APIs (2-way syncing)

Write back to APIs with actions or proxy requests.

## Troubleshoot errors & monitor

Navigate to the *Logs* tab to inspect potential errors & monitor sync executions.

**Questions, problems, feedback?** Please reach out in the Slack community.

This document has been revised according to your instructions. Let me know if further changes are required.