Postal

Postal provides a suite of installation tools and documentation for setting up and running the Postal email delivery platform. The repository includes scripts for quick deployment, detailed prerequisites, and guides covering getting started, configuration, and operation. It aims to simplify the installation process for developers and system administrators, offering both v2 and v3 installation scripts and links to comprehensive online documentation.

Postal is listed with 2 APIs on the APIs.io network. Tagged areas include Installation, Open Source, DevOps, Docker, and Tools.

The Postal catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Postal’s developer surface includes signup flow, pricing, documentation, getting-started guide, support, and 13 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

30.5/100 thin Agent 17/100 agent aware Full breakdown ↓
scored 2026-10-31 · rubric v0.25.0 · Show this score on your site →

2 APIs

InstallationOpen Source DevOps Docker Tools

Kin Score

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

Composite quality — 30.5/100 · thin

Contract Quality 3.7 / 21

Developer Ergonomics 4.5 / 17

Access Clarity 9.4 / 17

Operational Transparency 1.7 / 11

Contract Governance 2.2 / 10

Discoverability 4.9 / 9

Regulatory Posture 1.6 / 15

Agent readiness — 17/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 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 0 / 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 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):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
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)

11 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 17.6 — up to +20.6 composite points
Developer Ergonomics scores 26.2 — up to +14.8 composite points
Operational Transparency scores 15.8 — up to +10.9 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/postal-server/apis.yml: open an issue on github.com/api-evangelist/postal-server 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 2

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

Postal API

Postal provides an email delivery platform API documented at the official docs site.

Postal API

Postal API as documented publicly: 3 operations. Contract generated from the documentation by API Evangelist (2026-10-27); not the provider's own document.

Pricing Plans 1

Published pricing tiers and plan structures.

Postal Server Plans Pricing

3 plans

PLANS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Postal Server Context

1 classes · 2 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Postal API Rules

10 rules · 8 errors 1 warnings 1 info

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

GetApiV1MessagesMessageResponse

2 properties

JSON SCHEMA

Security Posture 1

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

Postal Server Domain Security

TLSv1.3 · HSTS

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

SignUp

SignUp

GettingStarted

GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Conformance

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

Security

Security

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Support

Support

Contact

Contact

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

Pricing

Pricing

Company 1

The organization behind the API

Website

Website

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: postal-server
name: Postal
image: https://opengraph.githubassets.com/76ef6940d715337154b85d755ee6d732954c120d6e6906e6f2a714915b5c4d4b/postalserver/install
description: Postal provides a suite of installation tools and documentation for setting up and running the Postal email delivery
  platform. The repository includes scripts for quick deployment, detailed prerequisites, and guides covering getting started,
  configuration, and operation. It aims to simplify the installation process for developers and system administrators, offering
  both v2 and v3 installation scripts and links to comprehensive online documentation.
url: https://raw.githubusercontent.com/api-evangelist/postal-server/refs/heads/main/apis.yml
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-27 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-27'
modified: '2026-10-27'
tags:
- Installation
- Open Source
- DevOps
- Docker
- Tools
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Plans
  url: plans/postal-server-plans-pricing.yml
- type: Spectral
  url: rules/postal-server-rules.yml
- type: JSONLD
  url: json-ld/postal-server-context.jsonld
- type: Vocabulary
  url: vocabulary/postal-server-vocabulary.yml
- type: DataModel
  url: data-model/postal-server-data-model.yml
- type: Conformance
  url: conformance/postal-server-conformance.yml
- type: Hosts
  url: hosts/postal-server-hosts.yml
- type: Vendors
  url: vendors/postal-server-vendors.yml
- type: SignUp
  url: https://github.com/signup?ref_cta=Sign+up&ref_loc=header+logged+out&ref_page=%2F%3Cuser-name%3E%2F%3Crepo-name%3E&source=header-repo&source_repo=postalserver%2Finstall
- type: Security
  url: https://github.com/postalserver/install/security
- type: Pricing
  url: https://github.com/pricing
- type: GitHubOrganization
  url: https://github.com/why-github
- type: DomainSecurity
  url: security/postal-server-domain-security.yml
- type: Website
  url: https://postalserver.io/
- type: Documentation
  url: https://docs.postalserver.io/
- type: GettingStarted
  url: https://docs.postalserver.io/getting-started/
- type: Support
  url: https://discord.postalserver.io
- type: Contact
  url: mailto:team@postalserver.io
apis:
- name: Postal API
  description: Postal provides an email delivery platform API documented at the official docs site.
  humanURL: https://docs.postalserver.io/
  baseURL: null
  aid: postal-server:postal-api
- aid: postal-server:postal-server-api
  name: Postal API
  description: 'Postal API as documented publicly: 3 operations. Contract generated from the documentation by API Evangelist
    (2026-10-27); not

    the provider''s own document.'
  humanURL: https://docs.postalserver.io/getting-started/prerequisites
  properties:
  - type: OpenAPI
    url: openapi/_ae-authored/postal-server-openapi-generated.yml
    x-provenance: generated
  - type: JSONSchema
    url: json-schema/postal-server-get-api-v1-messages-message-response-schema.json
x-submission-probe: 301 (-> https://github.com/postalserver/install) 2026-10-25
x-coverage:
  state: unreadable
  reason: js-rendered-docs
  detail: Documentation site renders content via JavaScript, preventing machine‑readable spec discovery.
  evidence:
  - url: https://docs.postalserver.io/
    status: 200
  checked: '2026-10-27'
x-enrichment:
  date: '2026-10-27'
  status: enriched
  artifacts_added: 15
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Postal API — frequently asked questions

Does Postal have an API?

Yes. APIs.io lists 2 APIs from Postal, including Postal API and Postal API.

Is there an OpenAPI specification for the Postal API?

Yes. APIs.io indexes 2 OpenAPI specifications for Postal, each linked for download from this page.

How do I authenticate with the Postal API?

Postal uses bearer-token authentication.

How much does the Postal API cost?

APIs.io lists 3 pricing plans for Postal, with each plan's price, limits and inclusions under Pricing Plans on this page.

Is the Postal API ready for AI agents?

Postal has a Kin Score of 30.5 out of 100 (thin) and an Agent Readiness score of 17.3 (agent-aware), scored by API Evangelist on 2026-10-31.

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