# Versioning

> The Emailit API is on version 2. How the version is set, what changes without a new version, the deprecated v1 API and the move to prefixed object IDs.

The API version is part of the base URL, so every request states the version it was written for. This page explains which versions exist, what can change within a version, and how object IDs changed in 2026.

## Versions

| Version | Base URL | Status |
| --- | --- | --- |
| v2 | `https://api.emailit.com/v2` | Current. Released in October 2025. Everything in this reference is v2. |
| v1 | `https://api.emailit.com/v1` | Deprecated. The previous generation of the API. It gets no new features and is no longer documented. |

If you still call v1, move your integration to v2. The [SDKs](/docs/sdks/) all use v2.

## Changes within v2

Emailit adds to v2 without changing the version in the URL. These changes can happen at any time:

- New endpoints and resources.
- New optional request parameters and headers.
- New fields in response objects and webhook payloads.
- New event types, statuses and other enum values.

Write clients that tolerate them: ignore response fields you don't recognize, don't fail on an unknown status or event type, and don't depend on the order of fields in a JSON object.

Changes to the API are announced in the [changelog](/docs/changelog/).

## Object IDs

In January 2026, every object moved to prefixed IDs: a type prefix followed by 27 letters and digits, such as `em_4KYof1ZzXndZE2VPi0DgULiekG8` for an email or `dom_4K468YrjOkR1wwdhqiO0G9XEUey` for a domain. All endpoints take and return these IDs. See [Object IDs](/docs/api-reference/#object-ids) for every prefix.

- Store IDs as strings, and compare them exactly. They're case-sensitive.
- Sending domains that existed before the change keep IDs that start with `sd_` or `sed_`. They work everywhere a `dom_` ID does, so don't validate domain IDs by prefix.
- API keys are secrets, not IDs. New keys start with `secret_`, and older keys without the prefix keep working. An API key's ID starts with `key_`.

## Related

  - [Changelog](/docs/changelog/): New features and changes, newest first.
  - [API reference](/docs/api-reference/): Base URL, authentication and resources.

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Source: https://emailit.com/docs/api-reference/versioning/