---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/sendgrid/ui/account-and-settings/safely-test-your-sending-speed#article
headline: Safely Test Your Sending Speed
description: Test Twilio SendGrid relay speeds at high volumes without affecting your sender reputation by sending messages to the @sink.sendgrid.net test domain.
url: https://www.twilio.com/docs/sendgrid/ui/account-and-settings/safely-test-your-sending-speed
inLanguage: en
dateModified: 2026-07-23T16:57:51.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# Safely Test Your Sending Speed

To test how quickly you can send multiple messages through Twilio SendGrid without affecting your sender reputation, send your test messages to any address at the **@sink.sendgrid.net** domain.

Twilio SendGrid provides this domain so you can test relay speeds at higher volumes using your standard integration practices. All messages sent to this domain are accepted for delivery and then immediately deleted. Sending to this domain doesn't contribute to the [IP warmup process](/docs/sendgrid/concepts/reputation/warm-up-ip-addresses) if you have an account with a dedicated IP address.

> \[!NOTE]
>
> Please be aware that all of the messages you send to this domain will still
> consume billable email credits for your account!

If you are looking to test your API integration, you can enable the `sandbox_mode` in the [`mail_settings` parameters of our Mail Send API](/docs/sendgrid/for-developers/sending-email/sandbox-mode/). **This will allow you to validate each parameter you include, and the structure of your JSON payload, all without actually sending a message.**

> \[!NOTE]
>
> `sandbox_mode` is not available for other endpoints, only `mail_send`.