established · 0.1 marketcapability domainresource

SMTP

Score 24.0 / 100 20 providers +6 via APIs 8 APIs Search apis.io →
Variants seen in the corpus: Simple Mail Transfer ProtocolSMTP

Providers using this tag (20)

Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.

Exemplar 7 Complete, well-documented, and agent-ready
AhaSendEmailTransactional EmailDeveloper Tools2 APIs84.3SendGridEmailEmail APIMarketing Email44 APIs82.4Amazon SESEmailEmail DeliverabilityEmail ServiceMarketing Email2 APIs80.5PostmarkEmailMessagingTransactional EmailDeliverability3 APIs70.2MailosaurEmail TestingSMS TestingDeveloper ToolsQA Automation1 API69.2SMTP2GOEmailEmail DeliveryTransactional Email1 API69.0MailboxlayerEmailEmail VerificationMX Records2 APIs68.9
Strong 3 Solid coverage with minor gaps
MoosendEmail MarketingMarketing AutomationCampaignsMailing Lists1 API62.1AgentMailCompanyArtificial IntelligenceEmailAI Agents1 API60.2MailerSendEmailTransactional EmailMarketing1 API57.4
Developing 3 Usable, with meaningful gaps to close
uCheckerEmail VerificationEmailDNS1 API47.7SparkPostEmailTransactional EmailMarketing EmailEmail Delivery10 APIs43.9MailjetEmailEmail DeliveryMarketing Email1 API41.6
Thin 5 Limited public surface area
Apache JamesEmailIMAPJavaJMAP1 API38.5MailerooEmailEmail DeliveryMarketing Email1 API36.6MailPaceEmailTransactional EmailMessaging1 API32.8MailgunEmailTransactional EmailEmail Verification1 API30.9EmailEngineEmailEmail APIIMAP13 APIs26.6
Emerging 1 Early or largely undocumented
SMTPEmailInternet StandardsIETF2 APIs13.0
Minimal 1 Almost no public developer surface
PostfixEmailMail ServerMTA1 API9.1

APIs with this tag (8)

Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →

Exemplar 2 Complete, well-documented, and agent-ready
HubSpot Transactional Email APIThe transactional email API enables sending template-based transactional emails through HubSpot using the S...91.6Harness SMTP APIThis contains APIs related to SmtpConfig as defined in Harness90.7
Strong 3 Solid coverage with minor gaps
Zoho ZeptoMailThe Zoho ZeptoMail API provides REST endpoints for sending transactional emails such as OTPs, password rese...65.1Smartlead Email Accounts APIEndpoints to add, list, update, and remove sender mailboxes (SMTP, Gmail, Outlook), assign them to campaign...61.0Cisco Intersight Smtp APIThe smtp API from Cisco Intersight — 6 operation(s) for smtp.59.7
Developing 1 Usable, with meaningful gaps to close
Pure Storage SMTP APIManages Simple Mail Transfer Protocol (SMTP) settings. SMTP allows the array to send email notifications an...52.6
Emerging 1 Early or largely undocumented
RFC 5321 - Simple Mail Transfer ProtocolRFC 5321 is the IETF standard defining the Simple Mail Transfer Protocol. It specifies the client-server pr...13.0
Minimal 1 Almost no public developer surface
Postfix SMTPPostfix implements SMTP (RFC 5321) for sending and receiving electronic mail, with submission (port 587), S...9.1

Companies reaching this through an API (6)

These companies publish an API, specification or operation carrying “SMTP” but do not classify their business under it. Listed unranked and kept out of the count above, because one tagged operation is not a statement about what a company does.

Cisco Intersight Harness HubSpot Pure Storage Smartlead Zoho

Score breakdown

Frequency
40.3
log-scaled weighted occurrences
Breadth
0.5
spread across providers
Quality lift
63.1
mean composite of providers using it
Cohesion
8.1
strength of nearest seed neighbor

Where this tag sits

Email broader

Related tags

Transactional Email 14 co-occurrences Email Delivery 6 co-occurrences Deliverability 9 co-occurrences Marketing Email 5 co-occurrences Email 21 co-occurrences Domains 6 co-occurrences Templates 8 co-occurrences

Where this tag comes from

Provider tag20
Api tag8
Openapi tag1
Openapi op tag4

Work with this as data

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Tools for tags

7 MCP tools reach this
  • find_tagsBrowse and filter every tag in the catalog.
  • get_cohortThis tag as a scored cohort — every provider carrying it, with scores.
  • cohort_statsPRO — the distribution across this tag: mean, median, band split, adoption rates.
  • cohort_rankingsPRO — the leaderboard, on composite AND agent-readiness axes.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This tag 
curl "https://apis.io/api/v1/tags/smtp"
All tags 
curl "https://apis.io/api/v1/tags?limit=25"
As a scored cohort 
curl "https://apis.io/api/v1/cohorts/tag/smtp"
The distribution (Pro) 
curl "https://apis.io/api/v1/cohorts/tag/smtp/stats" \
  -H "X-API-Key: $APIS_IO_KEY"

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