receivemail.dev / compare

Free Mailosaur alternatives for email verification in tests

Mailosaur has no free plan. Free and cheaper alternatives for reading verification emails in tests compared — receivemail.dev, mail.tm, Mailsac, MailSlurp, testmail.app and more. Updated 26 October 2026.

Alternatives at a glance

Tool	Cost	Account	Read mail via API	Inbox privacy	Retention
receivemail.dev	Free, no signup; Pro $7/mo	None	Yes, no key needed	Private (per-mailbox secret)	Free 60 min, Pro 24 h
mail.tm	Free, no paid tiers	None (mailbox created via API)	Yes, no key; 8 req/s per IP	Private (password)	Not published
Mailsac	Free 1,500 ops/mo; from $18/mo	For API key / private inbox	Yes, with key	Public without account; 1 private address free	Plan-dependent
Mailinator	Public inboxes free; Verified Pro $0 on approval; Business $79/mo (yearly)	For private inboxes / API	Not on the public tier	Public, unless on a private domain	Temporary on the public tier
MailSlurp	Free: 100 inboxes, 500 emails/mo; from $19.99/mo	Required	Yes, with key	Private	Persistent
testmail.app	Free 100 emails/mo; from $9/mo (yearly)	Required	Full API from the $9 plan	Private namespace	Free 1 day
Mailpit	Free, self-hosted	None (you run it)	Yes (REST)	Your own server	Your choice

Checked against each vendor's pricing and docs pages on 26 October 2026. Plans change — confirm on their sites before you commit. Mailpit only catches mail your own app sends to it over SMTP; it can't receive from a third-party service sending to a public address.

Mailosaur is a polished, paid testing platform: dedicated email servers, a real domain per account, SMS testing with virtual numbers, deep assertions (SPF/DKIM/DMARC checks, spam scoring, link and attachment inspection), and first-party libraries for most test frameworks. For a QA team that tests email and SMS seriously, it's a strong tool and this page isn't trying to move you off it.

Plenty of projects, though, only need one thing from a tool like this: in an automated test, sign up and read back the verification email. For that, receivemail.dev does the job with no account and no cost — you create a disposable inbox with one unauthenticated POST and poll it for messages.

Side by side

	receivemail.dev	Mailosaur
Price	Free; Pro $7/mo	No free plan; 14-day trial, then from $20/mo billed annually
Signup / account	None	Required
Receive email via API	Yes	Yes
SMS / phone testing	No (see sms-florin)	Yes
Dedicated domain per account	No — shared domain, random address	Yes
Email auth checks (SPF/DKIM/DMARC), spam score	No	Yes
Official framework libraries	No — plain HTTP (plus a Playwright helper)	Yes, many
Inbox lifetime	Up to 60 min free, 24 h on Pro	Persistent
Best for	Reading a code/link in CI, hobby projects, OSS	QA teams testing email & SMS as a discipline

Mailosaur's plans and limits change over time — see mailosaur.com/pricing for current details.

When receivemail.dev is enough

The assertion you actually make is "a message arrived and it contains this code/link" — nothing about headers, deliverability, or spam.
You don't want another paid tool in the stack for one test.
Contributors should be able to run the suite without credentials.
It's a side project, a demo, or an open-source repo's CI.

When to choose Mailosaur instead

You test SMS and email and want them in one tool.
You assert on SPF/DKIM/DMARC, spam score, or rendered HTML.
You want a dedicated domain and persistent inboxes.
You want vendor-supported libraries and a support contract.
Deliverability itself is under test, not just message content.

Migrating a test

# Mailosaur: new MailosaurClient(key); server + messages.get(...)
resp=$(curl -s -X POST https://receivemail.dev/mailboxes)
addr=$(echo "$resp" | jq -r .address)
secret=$(echo "$resp" | jq -r .secret)

# ... run your signup against $addr ...

curl -s "https://receivemail.dev/mailboxes/$addr/messages" \
  -H "Authorization: Bearer $secret"
# => {"messages":[{"from_address":"...","subject":"...","body_text":"..."}]}

Playwright version and more detail: the CI testing guide.

Other alternatives people compare

MailSlurp — email infrastructure API, send + receive. See the MailSlurp comparison.
Mailinator — free public inboxes, paid private domains + API. See the Mailinator comparison.
Self-hosted (Mailpit, MailHog) — ideal when your own app sends the mail on the same network; not an option when a third party sends to a public address.

FAQ

Does Mailosaur have a free plan?

No. It offers a 14-day trial; paid plans start from $20/mo billed annually.

What's the cheapest Mailosaur alternative for CI email tests?

For reading a verification code or link, receivemail.dev and mail.tm are free with no signup. Mailsac, MailSlurp and testmail.app have free tiers that need an account.

Is there an alternative that also tests SMS?

None of the free email tools above receive SMS. For real UK numbers that receive verification texts, see sms-florin, from the maker of receivemail.dev.