smtpfa-st

SMTPfast provides a developer-friendly email API that offers full visibility into the email delivery pipeline, including sending, tracking opens, bounces, and webhook events. It features a free tier with 3,000 emails per month, detailed analytics, and tools for SPF, DKIM, and DMARC checking. The service emphasizes transparency and real‑time tracing of each email, catering to developers who need reliable transactional email capabilities.

smtpfa-st is listed with 1 API on the APIs.io network. Tagged areas include Company, Email, API, Transactional, and Developer.

The smtpfa-st catalog on APIs.io includes 1 event-driven AsyncAPI specification.

smtpfa-st’s developer surface includes getting-started guide, authentication, signup flow, changelog, documentation, API reference, pricing, and 17 more developer resources.

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50.0/100 developing Agent 39/100 agent ready Full breakdown ↓
scored 2026-10-31 · rubric v0.25.0 · Show this score on your site →

1 API

Company EmailAPITransactionalDeveloper

Kin Score

Kin Score How this is scored →
scored 2026-10-31 · rubric v0.25.0

Composite quality — 50.0/100 · developing

Contract Quality 8.3 / 21

Developer Ergonomics 10.1 / 17

Access Clarity 12.4 / 17

Operational Transparency 3.2 / 11

Contract Governance 1.7 / 10

Discoverability 5.6 / 9

Regulatory Posture 3.7 / 15

Agent readiness — 39/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link

6 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 39.0 — up to +15.3 composite points
Contract Governance scores 16.4 — up to +10.0 composite points
Operational Transparency scores 28.9 — up to +9.2 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/smtpfa-st/apis.yml: open an issue on github.com/api-evangelist/smtpfa-st to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

SMTPfast API

SMTPfast API provides email sending, domain management, webhooks and analytics.

Pricing Plans 1

Published pricing tiers and plan structures.

Smtpfa St Plans Pricing

4 plans

PLANS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Smtpfa St Webhooks

ASYNCAPI

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Smtpfa St Authentication

1 scheme

SECURITY

Smtpfa St Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

SignUp

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Webhooks

Webhooks

Conformance

Conformance

Build 4

SDKs, sample code, and the tooling you integrate with

Packages

Packages

SDKs

SDKs

GitHubOrganization

GitHubOrganization

Postman

Postman

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

ChangeLog

ChangeLog

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: smtpfa-st
name: smtpfa-st
image: https://smtpfa.st/api/og?title=SMTPfast+-+Email+API+for+Developers&description=Built+on+AWS+SES+with+webhooks%2C+analytics%2C+and+developer-friendly+pricing.&section=Email+API
description: SMTPfast provides a developer-friendly email API that offers full visibility into the email delivery pipeline,
  including sending, tracking opens, bounces, and webhook events. It features a free tier with 3,000 emails per month, detailed
  analytics, and tools for SPF, DKIM, and DMARC checking. The service emphasizes transparency and real‑time tracing of each
  email, catering to developers who need reliable transactional email capabilities.
url: https://artifacts.apis.io/smtpfa-st/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-31 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-31'
modified: '2026-10-31'
tags:
- Company
- Email
- API
- Transactional
- Developer
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: GettingStarted
  url: https://smtpfa.st/blog/getting-started
- type: Plans
  url: plans/smtpfa-st-plans-pricing.yml
- type: Webhooks
  url: asyncapi/smtpfa-st-webhooks.yml
- type: Authentication
  url: authentication/smtpfa-st-authentication.yml
- type: Conformance
  url: conformance/smtpfa-st-conformance.yml
- type: LLMsTxt
  url: llms/smtpfa-st-llms.txt
- type: WellKnown
  url: well-known/smtpfa-st-well-known.yml
- type: Hosts
  url: hosts/smtpfa-st-hosts.yml
- type: Vendors
  url: vendors/smtpfa-st-vendors.yml
- type: Packages
  url: packages/smtpfa-st-packages.yml
- type: SignUp
  url: https://smtpfa.st/register
- type: SDKs
  url: https://www.npmjs.com/package/@smtpfast/sdk
- type: GitHubOrganization
  url: https://github.com/smtpfast
- type: ChangeLog
  url: https://smtpfa.st/changelog
- type: DomainSecurity
  url: security/smtpfa-st-domain-security.yml
- type: Website
  url: https://smtpfa.st/
- type: Documentation
  url: https://smtpfa.st/docs
- type: APIReference
  url: https://smtpfa.st/api/v1/openapi.json
- type: Pricing
  url: https://smtpfa.st/pricing
- type: Blog
  url: https://smtpfa.st/blog
- type: Support
  url: https://smtpfa.st/status
- type: TermsOfService
  url: https://smtpfa.st/terms
- type: PrivacyPolicy
  url: https://smtpfa.st/privacy
- type: Postman
  url: https://www.postman.com/smtpfast/workspace
apis:
- name: SMTPfast API
  description: SMTPfast API provides email sending, domain management, webhooks and analytics.
  humanURL: https://smtpfa.st/docs
  baseURL: https://smtpfa.st/api
  aid: smtpfa-st:smtpfast-api
x-coverage:
  state: gated
  reason: partner-login
  method: derived
  generated: '2026-10-31'
  generator: derive-coverage.py (pre-flight evidence)
  detail: the company serves an API surface but requires credentials before any description of it can be read
  evidence:
  - url: https://smtpfa.st/api/mcp
    status: 401
  - url: https://smtpfa.st/
    status: 200
x-enrichment:
  date: '2026-10-31'
  status: enriched
  artifacts_added: 17
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

smtpfa-st API — frequently asked questions

Does smtpfa-st have an API?

Yes. APIs.io lists 1 API from smtpfa-st, including SMTPfast API.

How do I authenticate with the smtpfa-st API?

smtpfa-st documents its authentication (1 scheme). The details are profiled on APIs.io as Smtpfa St Authentication.

How much does the smtpfa-st API cost?

APIs.io lists 4 pricing plans for smtpfa-st, with each plan's price, limits and inclusions under Pricing Plans on this page.

Is the smtpfa-st API ready for AI agents?

smtpfa-st has a Kin Score of 50.0 out of 100 (developing) and an Agent Readiness score of 38.6 (agent-ready), scored by API Evangelist on 2026-10-31.

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