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

# API Introduction

> Base URL, authentication, versioning, and conventions

## Base URL

```
https://api.sftpsync.io
```

## Authentication

Every request requires a workspace API key sent via header:

```
X-API-Key: <your_api_key>
```

## Versioning

FileFeed uses **date-based API versions**, the same pattern Stripe and Twilio
use. Send the version you want to pin to as a header:

```
FileFeed-Version: 2026-05-25
```

If you omit the header, the API falls back to the **default version pinned
to your workspace** (set at signup; configurable from the dashboard). Older
workspaces remain on `2024-09-01` until they explicitly opt in.

### Available versions

| Version      | Status     | Notes                                                       |
| ------------ | ---------- | ----------------------------------------------------------- |
| `2026-05-25` | **Latest** | Renames `Client` → `Connection`. Identical shape, new name. |
| `2024-09-01` | Deprecated | Baseline. Sunsets on **2027-05-25**.                        |

See the [migration guide](/migration/v1-to-v2) for upgrade instructions and
the [changelog](/changelog) for the full version history.

### Response headers

Every response echoes the version the server applied:

```
FileFeed-Version: 2026-05-25
```

Deprecated routes additionally include:

```
Deprecation: true
Sunset: 2027-05-25
Link: <https://docs.filefeed.io/migration/v1-to-v2>; rel="deprecation",
      <https://api.sftpsync.io/connections>; rel="successor-version"
```

Watch for `Deprecation: true` in your integration's response handler — that
header is how you'll know a route you depend on is going away. The
[`@filefeed/sdk`](/api-library/overview) surfaces it through the
`onDeprecation` callback automatically.

## Pagination

* Page-based: `?page=1&limit=50`
* Offset-based (data pages): `?offset=0&limit=1000`

<Note>
  For a typed client, use the `@filefeed/sdk` [API Library](/api-library/overview).
  The SDK pins to a specific API version per release, so an SDK upgrade is what
  moves you between versions — never an out-of-band wire change.
</Note>