SMTP capture  ·  no-login review

Email review,
for the people who don't run
docker compose up.

MailSandbox captures every email your test environment sends, then gives you one link to paste in a Jira ticket. Your client opens it, reviews the email, approves the copy — all without logging in, installing anything, or asking what SMTP means.

No credit card
500 emails/mo free, forever
Self-hostable
mailsandbox.com/acme
just now
Subject
Welcome to Acme — please verify your email
from noreply@acme.test
Share with client
Active
mailsandbox.com/s/8j2k-q91x-vn7p
shared with sarah@acme.com 2m
opened no login required 1m
approved Sarah just now
§  comparison

Why not MailHog,
Mailpit, or MailTrap?

An honest answer, from someone who uses all of them. MailHog and Mailpit are excellent debug consoles — for the developer who wrote the code. They stop being useful the moment a non-engineer needs to see the email. MailTrap is built for QA teams behind a login. MailSandbox starts where both approaches stop: a link you paste in Jira, a client who clicks it, an email they approve.

OSS
MailHog
OSS
Mailpit
SaaS
MailTrap
This is us
MailSandbox
Captures real SMTP
Yes
Yes
Yes
Yes
Self-hosted option
Yes
Yes
No
Yes
Shareable review link, no login for reviewer
Not supported
Not supported
Login required
Yes — that's the point
Per-developer private inboxes
Single inbox
Single inbox
Yes
Yes
Paid plan starts at
Free (OSS)
Free (OSS)
~$15 / mo
$15 / mo
Best for
Local dev debugging
Local dev debugging
In-house QA teams
Agencies & stakeholder review

If you're a solo developer who only ever reviews your own emails, MailHog or Mailpit will serve you well — and we'll say so. If you work with clients, designers, PMs, or brand managers who need to approve email copy before it ships, that's the problem MailSandbox was built for.

§  how it works

Three steps.
No one needs an account.

Point your test environment at our SMTP host, copy the review link when an email comes in, paste it anywhere. That's the entire workflow. No servers to run, no client onboarding, no "just sign up for an account real quick."

01

Point your test env at our SMTP

Four lines in .env. Works with Laravel, Rails, Django, Node, anything that speaks SMTP. Every email your app sends now lands in MailSandbox instead of a real inbox.

.env
MAIL_HOST=smtp.mailsandbox.com
MAIL_PORT=2525
MAIL_USER=msb_a8f21c
MAIL_PASS=••••••••••
02

Copy the review link

Every captured email gets a signed, unique URL. Drop it in a Jira ticket, a Linear comment, a Slack thread, a client email. The link renders the full HTML email with device/client preview toggles.

mailsandbox.com/s/8j2k-q91x-vn7p
Valid for 90 days · revocable anytime
03

Your reviewer approves

They click. They see the email exactly as it will render. They approve, request changes, or comment. You see the activity log. No signup. No Zoom call. No screenshot chain.

opened sarah@acme.com 14:02
approved copy looks good to me! 14:03
§  in motion

Ninety seconds
end-to-end.

A narrated walkthrough of the full loop — configuring SMTP in a fresh Laravel app, capturing a password-reset email, pulling the share link, and watching a reviewer open it without an account. No cuts, no narration tricks, no "edit magic."

mailsandbox / demo.mp4
01:37
narrated walkthrough · recorded against production · 1080p
§  under the hood

Built for the engineer
who reads the docs.

The details the developer who configured the SMTP host actually cares about. Everything captured and indexed, everything scriptable, everything inspectable — so you can ship confidently instead of crossing your fingers.

Signed, revocable share URLs

Every share link is signed with a rotating secret, expires on a schedule you set, and can be revoked in one click. You see exactly who opened it, when, and from where.

mailsandbox.com/s/8j2k-q91x-vn7p
  ?expires=2026-07-12T10:00Z
  &sig=a8f2c1d•••••••••

Rendering preview across clients

See exactly how the email renders in Apple Mail, Outlook 2019, Gmail web, and mobile viewports before you ship. No more "it looked fine in my client."

Apple Mail
Outlook 2019
Gmail web
iOS

Automated email inspection

HTML/CSS support linting, broken-link detection, image size warnings, and table-width sanity checks — run automatically on every captured email.

inline CSS support
table width 620px — recommended ≤ 600px
alt text present on all images
all links resolve (3 checked)

Spam score analysis

Coming soon

SpamAssassin-compatible scoring for every captured email. Know whether your transactional template is headed for Promotions before your customers find out.

score 2.3 / 10
likely clean ≥ 5.0 at risk

Headers, raw source, attachments

Inspect every MIME part, every header, every DKIM signature. Download the raw .eml or any attachment as if you'd pulled it out of a real mailbox.

Message-ID: <a8f2@acme.test>
DKIM-Signature: v=1; a=rsa-sha256; d=acme
X-Mailer: Laravel/12.4.1
Content-Type: multipart/alternative;

Per-developer private inboxes

Give each engineer a personal isolated inbox that never leaks into the team's shared view. Local testing stays local. Client-facing emails stay deliberately shared.

@huub local / dev
@sarah staging / qa
@dev-bot ci / github-actions
§  pricing

Priced for the team
that uses it.

Start free forever. Upgrade the day your team outgrows the tier — not the day a trial clock runs out. No credit card to try it, no retention discounts, no dark patterns.

Save 20%

Free

For individuals

Free
forever
Emails / mo
500
Inboxes
3
Projects
1
Team members
1
  • SMTP capture & sandbox
  • Browser-based email preview
  • Team inbox access
  • No credit card required
Choose plan

Starter

For freelancers and hobbyists

$1513 / mo
billed monthly billed $150 / yr
Emails / mo
2,500
Inboxes
20
Projects
10
Team members
5
Everything in Free, plus:
  • Sharing emails with signed URLs
  • Automated email inspection
  • Spam score analysis soon
Choose plan
§  popular

Growth

For growing teams

$3227 / mo
billed monthly billed $320 / yr
Emails / mo
15,000
Inboxes
100
Projects
50
Team members
30
Everything in Starter, plus:
  • Private developer inboxes
Choose plan

Business

For large teams

$8974 / mo
billed monthly billed $890 / yr
Emails / mo
75,000
Inboxes
300
Projects
100
Team members
150
Everything in Growth, plus:

Scale headroom for teams sending tens of thousands of transactional emails each month.

Choose plan
§  get started

Start capturing test emails in
under sixty seconds.

Free tier: 500 emails per month, 3 inboxes, one shareable review link per email. No credit card, no trial clock, no "upgrade to unlock" dark patterns. Upgrade when your team outgrows it — not before.

Free plan includes
Emails per month 500
Inboxes 3
Projects 1
Max email size 5 MB
Credit card not required