# SendGrid v3 API reference

The SendGrid v3 Web API provides a REST interface to send email at scale and ensure your application can handle high volumes.

The SendGrid API endpoints allow you to integrate with your tech stack to send transactional emails, create marketing campaigns, manage your contacts, and monitor the health of your email statistics.

This API reference provides complete documentation for every endpoint and operation. For an overview of using SendGrid APIs, see the [Getting Started](/docs/sendgrid/api-reference/how-to-use-the-sendgrid-v3-api) section.

## Additional resources

### Onboarding guide

For a full-featured guide to ensure you build your email program on a solid foundation, see the [Email API Onboarding guide](/docs/sendgrid/onboarding/email-api).

### Email API quickstarts

Jump to an email quickstart in your programming language of choice to implement the Mail Send API.

* [C#](/docs/sendgrid/for-developers/sending-email/email-api-quickstart-for-c)
* [Go](/docs/sendgrid/for-developers/sending-email/quickstart-go)
* [Java](/docs/sendgrid/for-developers/sending-email/email-quickstart-for-java)
* [Node.js](/docs/sendgrid/for-developers/sending-email/quickstart-nodejs)
* [PHP](/docs/sendgrid/for-developers/sending-email/quickstart-php)
* [Python](/docs/sendgrid/for-developers/sending-email/quickstart-python)
* [Ruby](/docs/sendgrid/for-developers/sending-email/quickstart-ruby)

### SDKs and tools

See our open-source SDKs and tools to integrate with SendGrid.

* [C#](https://github.com/sendgrid/sendgrid-csharp)
* [Go](https://github.com/sendgrid/sendgrid-go)
* [Java](https://github.com/sendgrid/sendgrid-java)
* [Node.js](https://github.com/sendgrid/sendgrid-nodejs)
* [PHP](https://github.com/sendgrid/sendgrid-php)
* [Python](https://github.com/sendgrid/sendgrid-python)
* [Ruby](https://github.com/sendgrid/sendgrid-ruby)
* [OpenAPI specification](https://github.com/twilio/sendgrid-oai)