Mailtrap

Free allowance: 4,000 emails per month and 150 emails per day on the free tier, 1 user, 1 domain, 3 days of logs
Verdict: caveatusable, with a named limit or an unprobed read path
Cost: free tier
Identity: emailno card, no phone
Binding limit: request-rate150 emails per day
Evidence: documented1 source; a first-party page was read and the sentence quoted
Freshness: stale on 2026-11-22checked 2026-10-22 (live); stale on 2026-11-22

Free tier	4,000 emails per month and 150 emails per day on the free tier, 1 user, 1 domain, 3 days of logs unit requests; metered on request-count
Price	none stated
Limits	request-rate (binding) 150 emails per day source counts of things, not rates, so no vocabulary kind names them: 1 user and 1 domain. the pricing page states 4,000 emails per month and 150 per day on the Email API/SMTP free tab, with the footnote that the email limit is per month and 'Shares quota between sending and receiving'. The page carries no separate sending sub-allowance
Identity	email an account
Egress	not applicable: an outbound sender
Retention	3 days of email logs on the free plan
Interface	rest the Mailtrap Email API and SMTP, on the Email API tab
Tooling	curl, any SMTP client
Composes with	150/day out with 4,000 in the pool, so it composes with a domain and with a launch that spikes for one day and then stops.
Reliability	the 4,000 is a sandbox-and-send pool; the pricing page presents the two tabs separately
Notes	The 4,000 headline is the trap: the free tier splits sending from sandbox testing and 150/day is what a launch meets.
Parsed numbers	has-free-tier 1

Evidence 1

date	source	what it proved
2026-10-22	mailtrap.io/pricing/	the Free column reads '4,000 emails', '150 emails/day', '1 user', '3 days of email logs' and '1 domain'

More fields 1

stale after days	90