SMTP Server Test

POST/api/v1/tools/smtp-test3 credits per callsmtpemailmail-serverstarttlsdeliverabilitytls

Speaks SMTP to the server: connects, reads the banner, sends EHLO, upgrades with STARTTLS where offered, inspects the TLS certificate, and - only when credentials are supplied - verifies that AUTH is accepted. It CANNOT send mail, by design, so it is not usable as a relay. Only ports 25, 465, 587 and 2525 are permitted, and private addresses are refused.

receipt_long

Why 3 credits?

A multi-step protocol session with a TLS handshake, held open for several seconds.

Any HTTP client works. Replace the key with one from your dashboard.

bash

curl -X POST https://toolkitbackend-j69m.onrender.com/api/v1/tools/smtp-test \
  -H "Authorization: Bearer tb_live_<your_api_key>" \
  -H "Content-Type: application/json" \
  -d '{
  "host": "smtp.example.com",
  "port": 587,
  "encryption": "starttls",
  "username": "postmaster@example.com"
}'

Input

Field	Type	Required	Default	Description
`host`	string	required	-	Mail server hostname.
`port`	integer	optional	587	25, 465, 587 or 2525.
`encryption`	string	optional	starttls	starttls, ssl or none. Port 465 always uses implicit TLS.
`username`	string	optional	-	Optional. Supplying credentials adds an AUTH check; they are used once and never stored.
`password`	string	optional	-	Optional, required only alongside username.

Output

Field	Type	Description
`encryption`	string	What the session ended up using: starttls, implicit-tls or none.
`authAttempted`	boolean	Whether credentials were supplied.
`authSucceeded`	boolean	Whether the server accepted them.
`certificateSubject`	string	TLS certificate subject.
`certificateIssuer`	string	TLS certificate issuer.
`certificateExpiresUtc`	string	Certificate expiry, UTC.
`extensions`	array	EHLO capabilities advertised.
`authMechanisms`	array	AUTH mechanisms offered.
`steps`	array	Each protocol step with its timing and reply.

Try it

Sends a real POST /api/v1/tools/smtp-test from your browser and charges 3 credits to your account.