Receive your app's emails at test addresses or your own domain, read them over the API, and check every code and link. Start free; pay when your team needs private domains, more volume or SSO. How the email testing API works
For one developer testing their own app.
For a team running email tests in CI, with shared domains and logins.
For larger QA groups with several apps and heavier suites.
For companies buying through procurement, at any volume.
Free, no signup needed: any @mailsac.com inbox receives mail. With a free account: an API key, 1 private address and 1,500 operations a month. Public inboxes are readable by anyone, so use made-up data.
Create a free account →An operation is one email received, one API call, or one forward or push (webhook, Slack, WebSocket). A typical test that receives an email and reads it uses about 3 operations, so the email estimates above assume 3.4 operations per email.
| Operations per month | ≈ Emails per month | Annual | Month to month |
|---|---|---|---|
| Up to 2 million | 600,000 | $7,500/yr | $799/mo |
| Up to 5 million | 1.5 million | $10,500/yr | $1,099/mo |
| Up to 10 million | 2.9 million | $15,000/yr | $1,599/mo |
| Up to 20 million | 5.9 million | $24,000/yr | $2,499/mo |
| Above 20 million | 5.9 million+ | +$1,000/yr per extra million | +$105/mo per extra million |
Available on every paid plan. Add to an existing plan from the plan limit increase page. Need more operations? Move up a plan, or talk to us about Enterprise above 2 million a month.
| Add-on | Monthly | Yearly |
|---|---|---|
| Extra custom domain | $7 | $75 |
| 250 more private addresses | $7 | $50 |
| 5,000 more stored messages | $10 | $100 |
| Feature | Free | Indie | Business | Business+ | Enterprise |
|---|---|---|---|---|---|
| Volume and storage | |||||
| Operations per month | 1,500 | 25,000 | 500,000 | 2,000,000 | 2M – 20M+ |
| Stored messagesAcross private addresses, domains and starred mail | 50 | 1,000 | 5,000 | 10,000 | 12,000+ |
| Message logs | 20 min | 20 min | 2 weeks+ | 2 weeks+ | 2 weeks+ |
| Addresses and domains | |||||
| Inboxes | Public | Private | Private | Private | Private |
| Custom domainsYour own domain, or a zero-setup msdc.co subdomain | 0 | 1 | 5 | 10 | 12+ |
| Private addressesForwarding, routing, POP3 and SMTP passwords | 1 | 50 | 250 | 500 | 480+ |
| Delete all mail on a domain | — | ✓ | ✓ | ✓ | ✓ |
| Custom public domainsShare a domain's mail with people outside your account | — | — | — | — | ✓ |
| Testing and integration | |||||
| REST API and email capture | ✓ | ✓ | ✓ | ✓ | ✓ |
| Webhooks and Slack forwarding | ✓ | ✓ | ✓ | ✓ | ✓ |
| WebSockets for addresses | ✓ | ✓ | ✓ | ✓ | ✓ |
| WebSockets for a whole domain | — | — | ✓ | ✓ | ✓ |
| Multiple named API keys | — | — | ✓ | ✓ | ✓ |
| Load testingSend at high rate; counted, not stored | — | — | ✓ | ✓ | ✓ |
| IP allowlistYour senders are never throttled | — | — | ✓ | ✓ | ✓ |
| Usage analytics | ✓ | ✓ | ✓ | ✓ | ✓ |
| Team and security | |||||
| Users | 1 | 1 | 5 | 10 | 25+ |
| SAML single sign-on | — | — | ✓ | ✓ | ✓ |
| Security questionnaires and vendor review | — | — | — | — | ✓ |
| Support and buying | |||||
| Support | Forum | Priority email | Email + 2h phone | ||
| Payment | — | Card | Card | Card; invoice or PO on annual | Annual: invoice, PO, ACH, wire · Monthly: card |
| Billing | — | Monthly or yearly | Monthly or yearly | Monthly or yearly | Annual or month to month |
If one person tests one app, Indie is enough. If several people share test domains or run suites in CI, Business gives you team logins, SSO and a key per pipeline. Choose Business+ when you run several apps or large suites, and Enterprise when your company buys through procurement or needs more than 2 million operations a month.
You get an email at 80% of your limit and another when you pass it. Everything keeps working until 125% of your limit; after that the API pauses until the 1st of the next month, unless you upgrade to a larger plan, which takes effect immediately.
Yes, on annual Business+ and Enterprise plans: invoice, purchase order, ACH or wire, or through our resellers SHI and SoftwareOne. Indie, Business and all monthly plans are paid by card.
Yes. Upgrades apply straight away, and unused time on your old plan is credited. You can cancel from the Billing page at any time: your plan keeps working until the end of the period you have paid for and then stops renewing. Removing a single add-on takes effect straight away, with the unused time credited to your next invoice.
Yes. Month-to-month Enterprise is billed by card at about 25% more than the annual price, with a 3-month minimum. It suits projects such as load tests and migrations. Security questionnaires and vendor reviews are included on annual plans and cost $1,000 once on month-to-month. You can switch to annual at any time.
Yes. Ask for an evaluation and we'll set up a time-limited trial, including burst throughput for load tests where you need it.
Mailsac runs on AWS in the United States. Enterprise customers get help with security questionnaires such as SIG and CyberGRX, plus our information assurance documentation.
Prices in US dollars, excluding tax. Card payments are processed by Stripe; we never see card details. By purchasing you agree to the terms of service and acceptable use policy and the privacy policy. Questions: support@team.mailsac.com
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