Comparisons / MailSlurp alternative
A smaller MailSlurp alternative for email tests
MailSlurp covers a lot of ground: receiving and sending email, SMS, phone numbers, permanent inboxes, and client libraries in more than twenty-five languages. inboxsink does one part of that: receive the email in a test, wait for it, give back the code or the link.
If you use MailSlurp for that part only, this page shows what changes. If you use the rest, stay where you are.
Side by side
| MailSlurp | inboxsink | |
|---|---|---|
| Free tier | 50 permanent inboxes, 100 new inboxes and 500 received emails a month, 1 seat | 1,000 API calls a month, no card |
| First paid plan | Starter: $19.99 a month. 250 new inboxes, 1,000 received emails a month | Developer: 29 € a month. 10,000 API calls, 1 custom domain, webhooks |
| Custom domain | Paid per use from Pro ($49.99 a month); one included in Growth ($129.99 a month) | One included in Developer |
| Waits for the email | Yes: waitForLatestEmail, waitForMatchingFirstEmail, waitForEmailCount | Yes: one wait route; waitForOtp and waitForLink in the JavaScript client |
| Verification code | Through an AI extraction preset (OTP_CODE) | Extracted from every message on arrival, no extra call. Digit codes only |
| Sending email | Yes | No, receive only |
| SMS and phone numbers | Yes, from Pro | No |
| Client libraries | 25+ languages | JavaScript; plain HTTP for the rest |
| Compliance | SOC 2 Type I badge; SOC 2, GDPR, CCPA listed on Enterprise | None certified |
The units differ: MailSlurp limits inboxes and received emails, inboxsink limits API calls. A typical test here makes three calls (create, wait, delete), so 1,000 calls is about 330 test runs.
Where MailSlurp is the better pick
- Your tests send email, not only receive it.
- You test SMS codes or need phone numbers.
- You want inboxes that stay around for months, not test inboxes that expire.
- You work in a language without an HTTP habit and want an official client.
Where inboxsink fits
- You only need to read a signup code or a magic link in a test, and would rather not learn a large API for that.
- The code should be there without asking for it: every message arrives with
otpandlinkalready filled in. - You need your own domain because the signup form refuses shared ones, and the Growth plan is more than the team wants to spend.
See it run: Playwright, Cypress, Selenium with Python.
Sources
Read on 13 September 2026. Prices change; check the vendor's page before deciding.
- Plans, limits, custom domains, compliance on Enterprise: app.mailslurp.com/pricing
- Wait methods and the
OTP_CODEpreset: mailslurp.com/docs/wait-for - Product scope and SOC 2 badge: mailslurp.com
- inboxsink: pricing and API reference
1,000 calls a month, no card asked. Enough to wire it into your test suite and see if it holds.
Then, when your tests start getting refused: a domain of your own is published nowhere, so it lands on no blocklist — 29 € a month.
Other comparisons
- A Mailinator alternative with private inboxes that wait
Mailinator's public inboxes are readable by anyone. inboxsink gives each test a private inbox that waits for the email and returns the code. Checked 13 Sep 2026.
- A Mailosaur alternative with a free tier
Mailosaur and inboxsink both wait for the email and extract the code. Checked 13 Sep 2026: a 14-day trial at Mailosaur, a free tier and a 29 € custom domain here.