Comparisons / Mailinator alternative
A Mailinator alternative with private inboxes that wait
Mailinator made the public disposable inbox famous: any address at mailinator.com receives mail, and anyone who types the name reads it. For a quick manual check that is perfect. In an automated test suite it causes two problems, privacy and waiting.
inboxsink's free web inbox works the same way, and we say so: whoever knows the address can read it. The difference is on the API side.
Side by side
| Mailinator | inboxsink | |
|---|---|---|
| Public inboxes | Yes, with "NO privacy"; deleted after a few hours | Yes on the web, readable by whoever knows the address; deleted after one hour |
| Private inboxes from the API | On a private domain, with a subscription | Any inbox created with an API key, free tier included: only that key reads it |
| Waits for the email | No wait or long-poll route in the API documentation | Yes: one route held open up to 120 s, answers the moment the mail lands |
| Codes and links | A route lists the links of a message; no code extraction documented | otp and link extracted on arrival |
| Custom domain | Private domain with a subscription (plan not confirmed) | One included in Developer, 29 € a month |
| SMS | Yes, a team SMS number | No |
| Webhooks and routing | Webhooks and routing rules | Signed webhooks on the Developer plan; no routing rules |
| Client libraries | Java, JavaScript, C#, Go, Ruby | JavaScript; plain HTTP for the rest |
| Price | Not confirmed: the pricing page could not be read on 13 Sep 2026 | Free: 1,000 API calls a month. Developer: 29 € a month |
Why a public inbox is a problem in a test suite
A verification email in a public inbox can be read by someone else before your test reads it, or instead of it. If two runs of the suite use the same inbox name, one of them can pick up the other's code. With a private inbox per test, neither can happen: the address is random, and the API refuses to show the inbox to any other key.
Why waiting matters
Without a wait route, a test has to poll: ask for the latest message, sleep, ask again. The sleep is either too long, and the suite crawls, or too short, and the test fails on a slow day. inboxsink holds one request open and answers as soon as the message is stored. In our Playwright run the code came back 1.3 to 1.6 seconds after the click, sending included.
Where Mailinator is the better pick
- You also test SMS.
- You rely on routing rules to forward or process mail by pattern.
- You need SSO or an official client in C#, Go or Ruby.
- You mostly check emails by hand, and a public inbox is all you need.
See the private-inbox pattern run against the real service: Playwright, Cypress, Selenium with Python.
Sources
Read on 13 September 2026.
- Public inbox privacy and retention, private domains, links route, SMS, webhooks and routing rules, client libraries: Mailinator API documentation
- Prices: mailinator.com/pricing (not readable by our checker on that date)
- 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 smaller MailSlurp alternative for email tests
MailSlurp vs inboxsink for email tests, prices checked 13 Sep 2026: the free tiers, where MailSlurp does more (SMS, 25+ SDKs), and what a custom domain costs.
- 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.