---
title: "See which service sent an email"
description: "A mark beside the sender names the mail service a message was sent with, such as Gmail, Mailchimp or SendGrid, and forwarded mail is marked too."
url: "https://openemail.uk/features/sent-with"
---

[Safety & authenticity](https://openemail.uk/features.md#safety)

# Which service sent it The service behind the sender.

Beside the sender, a mark names the service a message was sent with, from Gmail and Outlook to SendGrid and Mailchimp. Mail that reached you through a forward says so too.

[Open mail](https://openemail.uk/mail/inbox) [Get Started](https://openemail.uk/signup.md)[All features](https://openemail.uk/features.md)

In short

## How can you tell which service sent an email?

A sending service leaves traces in the headers of what it sends: the key it signs with, headers of its own, the domain in the Message-ID or the name of its mail program. OpenEmail reads them as a message arrives and names the service beside the sender.

How it works

## Read from the headers, in order

As a message arrives, the signing key is read first, then the service’s own headers, the domain in the Message-ID and the mail program it names.

## Forwards say so

Mail that reached you through a forward gets a Forwarded badge by the To line and a note naming the address it was forwarded from. Mail addressed to someone else, such as a copy passed on to you, says Sent to that address instead.

## In the API as sentWith

The REST API and the SDK return the service as sentWith and the forward as forwardedFrom on every message. The MCP server includes both when it reads a conversation.

What you get

## In the product today

Listed in Details

Details lists the service too, as Sent with.

Your own mail

Your own mail carries the OpenEmail mark, as does mail from any domain that sends through OpenEmail.

Replies come from you

Replies always go out from one of your own addresses, forwarded mail included.

Good practice

## Getting the most out of it

1. 01
   
   Read it with the sender checks
   
   The mark names the service, and the sender checks under Details show whether the message came from the domain it claims.
2. 02
   
   Read the forward note
   
   It names the address the mail was forwarded from, and your reply goes out from one of your own addresses.
3. 03
   
   Sort by sentWith in your own tools
   
   The REST API and the SDK return sentWith on every message, so a script can tell mail sent with Mailchimp from mail sent with Gmail.

Questions

## Asked often

Keep going

## Works well with

Verified sender

A mark beside the sender when the sending domain’s published records line up.

Sender research & look-alike domains

Who is this, in fifty words, and is the domain a look-alike?

Start

## Your domain, your mail.

Point a domain at OpenEmail and read it in a mailbox built around it. The free plan covers one domain.

[Open mail](https://openemail.uk/mail/inbox) [Get Started](https://openemail.uk/signup.md)[Read the reference](https://openemail.uk/docs/knowledge/safety/sent-with.md)