Email testing for agencies.
The fake SMTP sandbox that catches emails from any staging environment. And organizes them for all of your clients and projects.
Happily used by teams worldwide
# How it works
Point your SMTP here
Four lines in .env. Works with anything that speaks SMTP: Laravel, Rails, Django, Node, or a raw socket.
MAIL_HOST=smtp.mailsandbox.com MAIL_PORT=2525 MAIL_USER=msb_a8f21c MAIL_PASS=••••••••••
We catch every email
Password resets, receipts, digests: every message your app tries to send is captured the instant it leaves, with the full HTML intact. Nothing reaches a real recipient.
Review, sorted by client + project
Every inbox belongs to a project, every project to a client, the structure your agency already thinks in. Open a message to review the full HTML, then share a link so clients can check it without an account.
# Walkthrough
# Features
Everything you need to catch, review, and share the emails your app sends, and nothing you don't.
A real fake SMTP
Catches every message on a standard SMTP endpoint and stops it there. Nothing is ever relayed to a real recipient.
Full HTML preview
See each email rendered exactly as it will land in an inbox, with the raw source one click away.
Client + project structure
Unlimited inboxes grouped by project, projects by client. The structure your agency already thinks in.
Shareable review links
Send a signed link. Reviewers approve or comment without an account, and you can revoke it anytime.
Spam score analysis
Every captured email is scored, so you catch deliverability issues before your client ever does.
Whitelabel subdomains
Serve review pages from your own domain, with SSL. Clients see your studio, not ours.
# Pricing
Free
For individuals
- Emails / mo
- 500
- Inboxes
- 3
- Projects
- 1
- Team members
- 1
- SMTP capture & sandbox
- Browser-based email preview
- Team inbox access
- No credit card required
Starter
For freelancers and hobbyists
- Emails / mo
- 2,500
- Inboxes
- 20
- Projects
- 10
- Team members
- 5
- Sharing emails with signed URLs
- Automated email inspection
- Spam score analysis soon
Growth
For growing teams
- Emails / mo
- 15,000
- Inboxes
- 100
- Projects
- 50
- Team members
- 30
- Private developer inboxes
Business
For large teams
- Emails / mo
- 75,000
- Inboxes
- 300
- Projects
- 100
- Team members
- 150
Scale headroom for teams sending tens of thousands of transactional emails each month.
# FAQ
Still unsure about something? Read the docs or just start free. The answer is usually "yes, and it took four lines."
Correct. MailSandbox accepts mail on a standard SMTP endpoint and stops it there. Every message is captured, rendered, and stored for review. None of it is ever relayed to the real recipient. Point staging at it and you can send a thousand password resets without a single one landing in an actual inbox.
Captured emails are retained per your plan and can be deleted anytime, manually or on an automatic schedule. Share links are signed with a rotating secret, expire on a window you set, and are revocable in one click. Reviewers only ever reach the single email you shared, never your dashboard or another client.
If it speaks SMTP, it works: Laravel, Rails, Django, Node/Nodemailer, or a raw socket. There is no SDK to install and nothing proprietary to adopt: you change the host, port, and credentials and you are done. Switching back is exactly as easy, so there is no lock-in.
Yes. Pricing scales on volume and features, not on how many clients you serve, so adding a client or spinning up a new project never costs extra. One flat plan, every client included. Agencies tend to do the math per client and find it is a rounding error.
Anytime. Revoke a single link, regenerate it with a fresh signature, or let it expire on schedule. You also see exactly who opened it and when, so you know a review actually happened.
No. That is the whole point. A reviewer clicks the link, sees the email exactly as it will render, and approves or comments. No signup, no password, no "quick account" friction between you and their sign-off.