Test emails.
Not your users.

SMTPBox catches emails from development, staging and automated tests before they reach real customers.

SMTP, API, team workspaces and 2,500 sandbox emails every month - free.

Start testing free →View documentation →

No credit card
Setup in under a minute
2,500 emails / month
Multiple team members

>_ SMTPBox

SUBJECT

Welcome to Acme

Captured

From: hello@acme.dev
To: charles@example.com

Welcome, Charles

Your account is ready. Verify your email to get started.

This email was safely captured by SMTPBox.

Works with SMTP-capable stacks including

PHPLaravelSymfonyNode.jsPythonDjangoRuby.NETWordPressPlaywright

SMTP INTEGRATION

Your app already sends email.
Just point it at SMTPBox.

No SDK, package or code rewrite. Change your SMTP credentials and send exactly as you do today.

✓ Works with every SMTP-capable framework
✓ STARTTLS on 587/2525 and implicit TLS on 465
✓ Credentials scoped to each inbox

Read the documentation →

MAIL_MAILER=smtp

MAIL_HOST=smtp.smtpbox.dev
MAIL_PORT=587
MAIL_USERNAME=sb_7M9xKp82
MAIL_PASSWORD=••••••••••••
MAIL_ENCRYPTION=tls

$ php artisan tinker
> Mail::to('test@example.com')->send(new WelcomeEmail());

✓ Captured by SMTPBox

HOW IT WORKS

From config to captured
in three small steps.

□

Create a box

Keep local development, staging, CI tests and feature branches in separate inboxes.

customer-portal / staging

↗

Use your credentials

Point your existing mailer at our SMTP server, or send with the REST API.

smtp.smtpbox.dev:587

⌕

Inspect every email

Preview HTML, text, headers, attachments, links, raw MIME and delivery metadata.

250 Message captured

BUILT TO DEBUG

Everything you need
to test email.

No generic collaboration fluff. Just the tools developers need to catch, inspect and automate.

↘

SMTP sandbox

Drop SMTPBox into your existing mail configuration. No SDK required, and nothing reaches the original recipient.

smtp.smtpbox.dev:587

17:03:12 CONNECT 192.168.1.42

17:03:12 AUTH authenticated

17:03:13 DATA 18.4 KB

17:03:13 STORED msg_7Jd92K ✓

{ }

REST API

Create inboxes, retrieve messages and automate testing with clean JSON.

GET /v1/inboxes/{id}/messages

◫

Instant preview

Switch between rendered HTML, source, plain text and raw MIME.

PreviewHTMLText

⌕

Message search

Search sender, recipient and subject to find the message your test generated.

welcome@example.test

⌁

Link detection

Extract and inspect every verification, reset and unsubscribe URL.

✓ /verify/8fKs2

♙

Team workspaces

Invite the developers and QA engineers who need access-without paying per seat.

⚡

CI/CD friendly

Made for GitHub Actions, GitLab CI, Jenkins, CircleCI and Azure DevOps.

A UI THAT STAYS OUT OF YOUR WAY

Debug email without
debugging your email tool.

A focused interface for the details that matter-without enterprise dashboard clutter.

Customer Portal

development

Welcome to Acmehello@acme.devnow

Reset your passwordsecurity@acme.dev46s

Your invoice is readybilling@acme.dev2m

Welcome to Acme

hello@acme.dev → charles@example.com

Welcome, Charles

Thanks for joining Acme. Confirm your email address to finish setting up your account.

Received: SMTP · TLS 1.3
Size: 24.6 KB
Message-ID: <8dc92@example.com>
Status: Processed

API-FIRST EMAIL TESTING

Built for humans.
And your test suite.

Inspect messages in the dashboard or let your automated tests wait for the exact email they triggered.

✓ Search and retrieve messages
✓ Assert recipients, content and links
✓ Webhooks for instant workflows
✓ Delete test data when you're done

Explore the API reference →

terminal

$ curl https://api.smtpbox.dev/v1/inboxes/box_82K/messages \
  -H "Authorization: Bearer sb_test_xxxxx"

{
  "data": [{
    "id": "msg_71KJ92",
    "to": ["charles@example.com"],
    "subject": "Welcome to Example"
  }]
}

registration.test.js ● PASS

const email = await smtpbox.waitFor({
  to: 'customer@example.com',
  subject: 'Reset your password'
});

expect(email.links).toContain(resetUrl); ✓

CATCH-ALL INBOUND EMAIL

Need inbound email too?

Enable an optional generated catch-all address. Use any alias you like—everything lands safely in the same test inbox.

anything@a1b2c3.inbound.smtpbox.dev

Registration testsTicketing systemsReply-to testingAutomated QA

alice@a1b2c3.inbound.smtpbox.dev →

billing@a1b2c3.inbound.smtpbox.dev →

reset-test-382@a1b2c3.inbound.smtpbox.dev →

development 3 messages

FRAMEWORKS

Drop SMTPBox into your stack.

If it speaks SMTP, it works with SMTPBox.

◈

Laravel

MAIL_HOST=smtp.smtpbox.dev

⬡

Node.js

nodemailer.createTransport(...)

🐘

PHP

$mailer->send($email)

♢

Symfony

MAILER_DSN=smtp://...

Python

smtplib.SMTP(...)

.NET

new SmtpClient(...)

A SIMPLE OFFER

Email testing without
pricing guesswork.

SMTPBox offers a permanent free sandbox and one paid plan. Confirm current third-party features and pricing with each provider before choosing.

Compare Mailtrap Compare MailSlurp Compare Mailpit Compare MailHog

SIMPLE PRICING

Pricing without the spreadsheet.

Start free. Upgrade when you're actually using it.

FREE

£0 / forever

◇

2,500 emails / month

5 team members
Unlimited projects & inboxes
SMTP and REST API access
Webhooks and link extraction
HTML, text, headers & source
Attachments and search
7-day retention

Start for free →No credit card required

UNLIMITED

£14.99 / month

∞

Unlimited test emails*

Everything in Free
Unlimited team members
Unlimited projects & inboxes
30-day retention
Higher API rate limits
Billing Portal management
No per-seat surprises

Go unlimited →Cancel any time

*Fair usage applies. SMTPBox is designed for development and testing environments, not production email delivery or permanent email storage.

HOSTED FOR YOUR WHOLE TEAM

Mailpit locally.
SMTPBox everywhere else.

Mailpit and MailHog are brilliant for local development. SMTPBox gives your shared environments the same simplicity without another service to run.

01Shared stagingOne inbox the whole team can inspect.

02CI pipelinesAssert emails through an API built for tests.

03Remote developmentWorks wherever your development environment lives.

04Feature environmentsSeparate boxes for every branch and preview.

SECURITY BY DESIGN

Test email is still data.

Safe defaults protect every message from connection to automatic deletion.

⌁

TLS encrypted SMTP

TLS supported across SMTP connections, with HTTPS for every dashboard and API request.

⌘

Scoped API keys

Separate sbx_api_... credentials and choose read-only or read/write access for each integration.

◷

Automatic deletion

Messages expire according to your retention period, or delete them immediately through the UI or API.

⊘

No production delivery

Sandbox messages are never forwarded to their original real-world recipients.

CLEAR PRODUCT BOUNDARIES

Built for testing.
Not sending newsletters.

✓ SMTPBox does

Catch development emails
Test transactional email flows
Inspect HTML, headers and links
Test registration and password resets
Power automated QA
Test inbound email workflows

× SMTPBox doesn't

Deliver production email
Send marketing campaigns
Replace SES, Postmark or SendGrid
Store your email forever
Send bulk email
Charge you automatically at your limit

Keep your existing production provider. SMTPBox sits safely in your development workflow.

FAQ

Questions, answered.

What is an email sandbox?

A safe inbox that captures mail from development and test environments. You can inspect the message without delivering it to a real recipient.

Will emails actually be delivered?

No. SMTPBox catches sandbox mail and never forwards it to the original recipient.

Can I use SMTPBox with Laravel or WordPress?

Yes. SMTPBox works with Laravel, WordPress and any other application that supports standard SMTP.

What happens after 2,500 emails?

We stop accepting new messages until your next monthly period or until you choose to upgrade. Existing captured messages stay available for their retention period. We never charge you automatically.

What does unlimited mean?

Unlimited for normal development and testing usage, subject to a fair-use policy. It does not cover production delivery, bulk sending or permanent storage.

Can automated tests read emails?

Yes. The REST API can wait for, search and retrieve messages so your tests can assert recipients, content and links.

How long are emails stored?

Messages are stored for 7 days on Free and 30 days on Unlimited. You can delete any message immediately.

smtpbox - zsh

$ smtpbox init

✓ Workspace created

✓ Inbox ready

✓ SMTP credentials generated

Ready to catch your first email.

READY WHEN YOU ARE

Stop accidentally
emailing customers.

Create your first SMTP sandbox in less than a minute.

Start testing free →No card required · 2,500 emails every month

Test emails.Not your users.

Welcome to Acme

Welcome, Charles

Your app already sends email.Just point it at SMTPBox.

From config to capturedin three small steps.

Create a box

Use your credentials

Inspect every email

Everything you needto test email.

SMTP sandbox

REST API

Instant preview

Message search

Link detection

Team workspaces

CI/CD friendly

Debug email withoutdebugging your email tool.

Welcome, Charles

Built for humans.And your test suite.

Need inbound email too?

Drop SMTPBox into your stack.

Laravel

Node.js

PHP

Symfony

Python

.NET

Email testing withoutpricing guesswork.

Pricing without the spreadsheet.

Mailpit locally.SMTPBox everywhere else.

Test email is still data.

TLS encrypted SMTP

Scoped API keys

Automatic deletion

No production delivery

Built for testing.Not sending newsletters.

✓ SMTPBox does

× SMTPBox doesn't

Questions, answered.

Stop accidentallyemailing customers.

Test emails.
Not your users.

Your app already sends email.
Just point it at SMTPBox.

From config to captured
in three small steps.

Everything you need
to test email.

Debug email without
debugging your email tool.

Built for humans.
And your test suite.

Email testing without
pricing guesswork.

Mailpit locally.
SMTPBox everywhere else.

Built for testing.
Not sending newsletters.

Stop accidentally
emailing customers.