Best Mailcrab Alternative for Testing
Use the Best Mailcrab alternative for testing emails, SMS, webhooks, and MFA. Test complete user flows in one unified sandbox — faster, safer, built for developers.
Replace multiple testing tools with one platform
Simulate real production flows safely
Built for developers and growing teams
MailCrab or Zunoy Sandbox: where does each fit?
MailCrab is a fast, lightweight way to catch email on a developer’s laptop. Zunoy Sandbox covers the next step: a staging inbox that QA, designers and clients can all open, where every email is checked before it ships.
Key takeaways
Change your staging SMTP host to mock-smtp.zunoy.com (port 8136, SSL) and add your inbox username and password. No code changes.
Hosted for you, with one isolated inbox per environment, so there is no shared container to keep running.
Forward chosen emails to a client’s or designer’s real inbox, or share a read-only link, without giving them access to Sandbox.
Every email gets HTML and link checks, and you can add failure simulation and firewall rules, plus SMS, webhook and TOTP testing.
Free forever plan with no credit card. You can keep MailCrab for local work and use Sandbox for shared environments.
COMPARISON
Zunoy Sandbox as a Mailcrab competitor
A feature-by-feature comparison across the tools teams typically juggle before switching.
FEATURES |  MAILCRAB |  ZUNOY SANDBOX |
|---|---|---|
Email Inbox |  | |
Authenticated Endpoints | No auth | Required on all |
Team shared inbox |  | |
Discord / Slack / Teams validation | | Real-time |
Alert integrations | | Slack, Discord, Teams |
Payload retention | Local only | Plan Based |
Public payload links | | |
Part of a full testing suite | | Email + SMS + TOTP |
SMS Inbox | | |
Webhook Inbox | | |
TOTP Testing | | |
Mailcrab suits lightweight self-hosted SMTP catching. This alternative to Mailcrab helps you test the entire product experience.
MIGRATION CHECKLIST
Best Mailcrab alternative in under 10 minutes.
No production changes required. No risk to real users.
- 01
Create a free Zunoy Sandbox account
Sign up at sandbox.zunoy.com. No credit card required. Your account includes Email, SMS, Webhooks, and TOTP from day one.
- 02
Create an inbox and copy your SMTP credentials
Create one inbox per environment — dev, staging, QA. Copy the SMTP host, port, username, and password from your inbox settings.
- 03
Update your staging environment config
Replace your Mailcrab SMTP host with mock-smtp.zunoy.com. Port 8136. SSL. That's the entire migration. No code changes.
- 04
Send a test email and verify it lands
Trigger any email flow in your staging environment. Open your Sandbox inbox. Email is already there — HTML rendered, scored, and visible to your whole team.
FOR LARGER TEAMS
We'll migrate your team for you. Hands-on. No extra charge.
If your team is on Mailcrab, or a custom enterprise plan and you want to switch — we handle the migration. Setup, environment config, team onboarding, and a live walkthrough. You stay focused on shipping. Available for teams of 5 or more. Typically completed in one working day.
White Glove Onboarding Process:
We audit your current staging email, SMS, webhook, and TOTP setup across all environments
We configure your Sandbox projects, inboxes, and credentials — dev, staging, QA — ready for your team to use
We update your environment configs and verify every email, SMS, and webhook flow lands correctly
Live 45-minute team walkthrough — every feature, every inbox, every alert integration
Shut down the old MailCrab container once everything has moved over, with no server left to patch
Book a 20-minute call and we'll handle the rest
White Glove Onboarding Process:
We audit your current staging email, SMS, webhook, and TOTP setup across all environments
We configure your Sandbox projects, inboxes, and credentials — dev, staging, QA — ready for your team to use
We update your environment configs and verify every email, SMS, and webhook flow lands correctly
Live 45-minute team walkthrough — every feature, every inbox, every alert integration
Shut down the old MailCrab container once everything has moved over, with no server left to patch
Book a 20-minute call and we'll handle the rest
Start with the Best Mailcrab alternative in under 5 minutes.
No Credit Card required
Free Forever
One Single Tool for - Email + SMS + Webhook + TOTP
Maintain customer trust - Test Alerts before your Users do
Setup under 5 minutes
Real human support by Zunoy Team
EMAIL INBOX — HIGHLIGHTS
Not just a message list. A full Email inspection Suite.
Not just SMTP capture. A full inspection suite with AI scoring, failure simulation, and per-inbox firewall rules that no single-channel tool offers.
HTML preview
See exactly how your email renders in Gmail, Outlook, Apple Mail, and mobile — before it reaches a single real inbox.
AI Scoring
HTML check, link check, spam analysis, performance, and AI content scoring — automatic on every email.
Failure Simulation
Six types of latency, SMTP errors, message loss, duplicates, corrupted attachments, rendering chaos. All simultaneous.
Inbox Firewall
Allowlist domains, block senders, and rate limit — per inbox. Real SMTP rejection to your app on every block.
Auto-Forward Rules
Forward emails to pre-verified addresses manually or automatically using match-any / match-all rules.
Team-Shared Inbox
Real-time for all team members. Everyone sees every email the moment it arrives — no forwarding, no screenshots.
WE ALSO HAVE
Email is just the Start. Three more channels in the Same Workspace.
Every channel your app uses to communicate with users — tested in one place, under one account, visible to your team.
SMS Testing
Test every OTP and transactional SMS without spending a rupee on real delivery. REST API, Sender ID, SMS templates - all are included.
Webhook Testing
Get a unique URL. Point any service at it. Every payload arrives in real time — inspectable, replayable, organised by project.
Shared MFA/TOTP Inbox
Test multi-factor authentication without using a real device. Upload QR codes or secrets and share TOTP access across your QA team. No authenticator app required.
HOW MUCH YOU SAVE
Free to Install Is Not the Same as Free to Run
MailCrab is free and open source, but someone still has to host it, keep it running, and find separate tools for SMS, webhooks and TOTP. Zunoy Sandbox covers all four with nothing to host.
What Running MailCrab Actually Takes
MailCrab
Open-source SMTP catcher$0 / mo
A server or container to run it
VPS, cloud VM or a shared dev box$5-$20/mo
Setup and upkeep
Docker, SMTP config, updates and storage cleanupEngineer time
SMS, webhook and TOTP testing
Not covered, needs separate toolsExtra tools
What it really costs
$5-$20/mo + your time
VS
With Zunoy Sandbox
FAQ'S
Questions about choosing an alternative to Mailcrab
Is Zunoy Sandbox the Best Mailcrab alternative?
Mailcrab is built for lightweight self-hosted SMTP catching. This Mailcrab competitor adds AI scoring, failure simulation, inbox firewall rules, and auto-forwarding — plus SMS, webhook, and TOTP testing.
Does switching require code changes?
For SMTP-based tools, no — just point at our mock server with new credentials. For API-based tools, it's a config swap with a familiar request/response shape.
What happens to my Mailcrab account during the switch?
Nothing — keep it running until your Sandbox environment is verified and your team has confirmed everything works.
Can I import my existing Mailcrab setup?
There's no automatic importer, but our white-glove onboarding recreates your inboxes, rules, and configuration for you — typically in one working day.
Is there a free plan like Mailcrab's?
Yes — the free plan includes email, SMS, webhook, and TOTP testing in one account, with no credit card required.
Can my whole team share the same inbox?
Yes — every Sandbox inbox is shared across your team by default, with no per-seat limits on who can view it.
THE ZUNOY SANDBOX SUITE
Beyond Mailcrab: the Best Mailcrab alternative for every channel
Your app sends emails, SMS, webhooks, and TOTP codes. Sandbox handles all four — in one workspace, under one account, visible to your whole team.
Email Inbox
SMTP capture & AI-scored previews
SMS Inbox
Virtual numbers for OTP & transactional SMS
Webhook Inbox
Real-time payloads, replayable & shareable
TOTP Inbox
Shared MFA codes, no authenticator app needed