# <Learn /> Blueink API Overview

## Introduction

This section contains an overview of concepts and usage of the Blueink API, including Authentication, Pagination, etc.

You can find a detailed documentation on API endpoints and operations in the [API Reference](/docs/api/) section.

If just starting with the Blueink API, you might want to check out the [Guides](/docs/guides/)
that supplement this API Overview.

## Versioning

The Blueink API uses semantic versioning. All minor and patch versions of the v2 API should be backwards
compatible.

- The latest version of the v2.X.X API is available at the path `/api/v2/`.

> **Deprecation**
>
>
> Old minor and patch versions are not accessible.
>

## HTTPS Only

> **Note**
>
>
> The Blueink API is only accessible via HTTPS.
>

## Rate Limits

- By default, Bundle creation requests (e.g a POST to /bundles) are limited to 200 / hour.
- Other API requests are limited to 2000 / hour.
- If you need higher limits, we are happy to accommodate. Please contact our team at [apisupport@blueink.com](mailto:apisupport@blueink.com).

## Test Mode

When creating envelopes with `is_test: true`, there are important restrictions to ensure test envelopes remain within your organization:

> **Test Mode Email Restrictions**
>
>
> **Email Verification Required**: Test envelopes can only be sent to email addresses that belong to users who exist in your Blueink account with verified email addresses.
>
> **Account User Restriction**: Test envelopes cannot be sent to arbitrary external email addresses - they must match existing account users.
>
> This ensures test envelopes stay within your organization during development and testing, preventing accidental delivery to external recipients.
>

## Additional Topics

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