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Best Open-Source SendGrid Alternatives (2026)

5 self-hostable, open-source projects that replace SendGrid — without per-email costs at scale. Each is scored for how hard it is to self-host, with one-click deploy options where they exist.

SendGrid charges per email, so transactional and marketing volume that's cheap at small scale becomes a meaningful line item as you grow. Running your own SMTP delivery platform turns that per-email cost into fixed infrastructure you control.

Our picks at a glance

Easiest to self-host
MailDev

Difficulty 2/5 — but note it's a local testing SMTP server with a web UI, not a production sender.

Most powerful
Postal

A complete self-hosted mail delivery platform positioned directly as a SendGrid/Mailgun alternative.

Most active
Postal

At ~16,600 stars it edges out the rest in momentum.

Best managed option
Forward Email

It's the only option here with a managed offering (managed:yes).

Compare all 5 alternatives

ProjectDeployManagedLicense
Postal
Ruby
17k ★
4/5
Involved
Docker
Docker Compose
+1
MIT18 days agoRepo
listmonk
Go
17k ★
3/5
Moderate
Docker
Docker Compose
+1
AGPL-3.014 days agoRepo
MailDev
JavaScript
5.9k ★
2/5
Easy
Docker
Manual
MIT5 months agoRepo
Haraka
JavaScript
5.2k ★
4/5
Involved
Docker
Manual
MIT1 month agoRepo
Forward Email
JavaScript
1.3k ★
5/5
Advanced
Manual
BUSL-1.17 days agoRepo

What to look for: Be clear whether you need production delivery (real outbound SMTP with reputation management) or just local testing — those are very different tools. For production, focus on deliverability, queuing, retries, and IP/domain warm-up; SPF/DKIM/DMARC setup is on you.

The alternatives, reviewed

  1. #1
    Postal
    Self-host: Involved

    Self-hosted mail delivery platform, a SendGrid/Mailgun alternative

    17k Ruby MIT 18 days ago
    How it compares to SendGrid
    • You are responsible for IP reputation, warmup, and deliverability
    • Requires MariaDB, RabbitMQ, and DNS/DKIM configuration to run
    • No marketing-campaign UI — it is a delivery engine, not a newsletter builder
    • Less hand-holding than managed providers for spam/blocklist issues
    RepoDetails & deploy →
  2. #2
    listmonk
    Self-host: Moderate

    High-performance self-hosted newsletter and mailing list manager

    17k Go AGPL-3.0 14 days ago
    How it compares to SendGrid
    • No built-in marketing automation/journey builder like Mailchimp
    • No bundled deliverability/IP reputation management — you supply your own SMTP/SES
    • No native landing page or e-commerce/CRM integrations
    • Reporting and analytics are basic compared to commercial suites
    RepoDetails & deploy →
  3. #3
    MailDev
    Self-host: Easy

    Local SMTP server with a web UI to test app-generated email

    5.9k JavaScript MIT 5 months ago
    How it compares to SendGrid
    • A development/testing catcher only — not for sending real production email
    • No deliverability, analytics, or campaign features
    • Not intended as a long-running production mail service
    • Limited storage/persistence for captured messages
    RepoDetails & deploy →
  4. #4
    Haraka
    Self-host: Involved

    Fast, highly extensible event-driven SMTP server in Node.js

    5.2k JavaScript MIT 1 month ago
    How it compares to SendGrid
    • Low-level MTA — no web UI, dashboards, or campaign tooling
    • Requires writing/configuring plugins for real-world setups
    • No built-in analytics, tracking, or template management
    • Deliverability and reputation management are entirely on you
    RepoDetails & deploy →
  5. #5
    Forward Email
    Self-host: Advanced

    Privacy-focused email service, an all-in-one Gmail and SaaS alternative

    1.3k JavaScript BUSL-1.1 7 days ago
    How it compares to SendGrid
    • Self-hosting is complex and far less documented than the hosted service
    • Newsletter/campaign tooling is thin compared to Mailchimp
    • BUSL-1.1 license is source-available, not fully OSI-open
    • Running production email requires significant infra and DNS expertise
    RepoDetails & deploy →

The verdict

For a real SendGrid replacement, Postal is the top pick — it's a full delivery platform built for exactly this and the most active project here. Use MailDev only for local email testing, and Haraka if you want to build custom SMTP routing on a fast, extensible engine.

Still deciding? Compare Postal vs listmonk side by side →

SendGrid alternatives — frequently asked questions

What's the best self-hosted SendGrid alternative?

Postal. It's a complete self-hosted mail delivery platform (~16,600 stars, MIT) positioned as a SendGrid/Mailgun alternative for transactional and bulk sending.

Which one is just for testing emails locally?

MailDev. It's a local SMTP server with a web UI to catch and inspect app-generated email during development — it does not deliver mail to real recipients.

Is there a free open-source SendGrid alternative?

Yes. Postal, MailDev, and Haraka are all MIT-licensed and free. listmonk is AGPL-3.0; Forward Email is BUSL-1.1.

Which alternative is easiest to self-host?

MailDev (difficulty 2/5) is easiest, but it's for testing only. Among production senders, listmonk is 3/5 while Postal and Haraka are 4/5.

Can I send marketing newsletters as well as transactional email?

Postal and Haraka handle transactional/outbound SMTP delivery. listmonk is the better fit for managing newsletters and mailing lists on top of an SMTP relay.

Do any of these offer managed hosting?

Only Forward Email (managed:yes). Postal, MailDev, Haraka, and listmonk are self-host only, so you run and maintain the delivery infrastructure yourself.

Keep exploring

All Email & Newsletters →Self-hosted directory →Easiest to self-host →
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