Alternatives

Products that do what Mailtree does

Free email sending API for developers

1
mailX by mailwarm▲602
Email deliverability toolkit for humans and AI agents
May 2026 · themailx.com
2
Resend▲1,326
Email for developers
2023 · resend.com
3
Send API by beehiiv▲259
Craft and send emails directly from your website or CMS
2025
4
SMTP Debug Tool▲346
Test and debug your SMTP connection, quickly and for free
2023
5
InboxSDK▲508
First usable API to write Gmail Apps for 1B active users
2015
6
Postal▲231
Open source mail delivery platform
2017
7
Mailazy▲203
Cloud email infrastructure for the internet
2022
8
Mailbird for Mac▲375
Email the way you like it, now on Mac
2024
9
Mailwarm 2.0▲683
The email warmup tool, upgraded for deliverability.
Jun 2026 · mailwarm.com
10
Mailbox for Mac (Beta)▲490
Fly through your email. Now on Mac
2014
11
SendgoMail▲88
Email sending made easy & affordable for free
2021
12
Unosend▲205
Send transactional + marketing email w/ 99.9% deliverability
Dec 2025
13
Mailshake▲601
A simple and easy to use solution for cold emails
2017
14IB
I built Mailhub – A scalable API for sending emails with ease not tears▲104
2024 · mailhub.sh
15
DevMail▲183
Email sandbox for software developers
2024
16
Mailmalade▲120
Build compatible HTML emails without coding knowledge
2014
17SE
Simple Email API▲15
2021 · batsign.me
18MS
Maildown – Super Simple Email API▲98
2019 · github.com
19
Sidemail.io▲204
Email delivery made simple for startups
2020
20
Mailmodo Email API▲244
APIs to send automated interactive emails with forms
2021
21
MailSlurp▲103
End-to-end email testing made easy
2018
22
MailMason▲141
A complete toolset to streamline building emails
2018
23
MailerLogic▲96
Email API with built-in deliverability intelligence
Apr 2026 · mailerlogic.com
24
Mailbutler 2.0▲162
Your personal assistant for Gmail and Apple Mail 📬
2018

Ranked by how close each launch is in meaning, then by votes. Refine with a description →