Stannp

Stannp is a direct mail platform that enables businesses to send physical postcards and letters programmatically via a REST API. The platform lets developers create campaigns, upload recipient lists, trigger individual mail pieces in real time, and track print and delivery status through webhooks and event endpoints. Authentication uses API key-based HTTP Basic Auth over HTTPS, and the API follows a simple JSON response envelope with success/data or success/error fields. Stannp serves businesses across the UK, US, and Canada with per-item pricing for letters and postcards at scale, and supports no-code integrations through Zapier and Make as well as official SDKs for PHP, Go, and C#.

Stannp publishes 7 APIs on the APIs.io network, including Account API, Campaigns API, Events API, and 4 more. Tagged areas include Direct Mail, Postcards, Letters, Print, and Physical Mail.

The Stannp catalog on APIs.io includes 1 event-driven AsyncAPI specification, 1 JSON-LD context, and 1 Spectral governance ruleset.

Stannp’s developer surface includes authentication, sandbox, documentation, API reference, getting-started guide, support, engineering blog, and 33 more developer resources.

🌐 Visit website 📡 Source on GitHub

78.5/100 exemplar ▬ flat Agent 39/100 agent ready Full breakdown ↓
scored 2026-08-25 · rubric v0.14.0

AccessFreemiumSelf serve⚡ Free to try

7 APIs 1 MCP Servers

Direct Mail Postcards Letters PrintPhysical MailMarketing Automation Campaigns Address Verification SMS Webhook Mailing Lists Fulfillment

Kin Score

Kin Score How this is scored →
scored 2026-08-25 · rubric v0.14.0

Composite quality — 78.5/100 · exemplar

Contract Quality 16.3 / 21

Developer Ergonomics 12.4 / 17

Access Clarity 15.9 / 17

Operational Transparency 7.6 / 11

Contract Governance 4.1 / 10

Discoverability 6.9 / 9

Regulatory Posture 8.5 / 15

Agent readiness — 39/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 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 Surface 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Telecommunications 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.

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/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/stannp: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 7

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

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Rate Limits 1

Documented rate limits and quota policies.

Stannp Rate Limits

4 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

JSON Schema 3

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

Examples 3

Example request and response payloads for these APIs.

Get Started 5

Portal, sign-up, and the first successful call

Sandbox

DeveloperPortal

GettingStarted

SignUp

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

MCPServer

AgentSkill

LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions

Idempotency

ErrorCatalog

DataModel

Conformance

Lifecycle

Webhooks

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

Packages

Packages

SDKs

SDKs

GitHubOrganization

GitHubOrganization

Access & Security 6

Authentication, authorization, and security posture

TrustCenter

TrustCenter

Compliance

Compliance

DomainSecurity

DomainSecurity

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

Authentication

Authentication

Operate 4

Status, limits, changes, and where to get help

StatusPage

Support

HelpCenter

RateLimits

Commercial 5

Pricing, plans, and the legal terms of use

Pricing

Plans

TermsOfService

PrivacyPolicy

FinOps

Company 3

The organization behind the API

Website

Website

LinkedIn

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Source (apis.yml)

aid: stannp
name: Stannp
description: 'Stannp is a direct mail platform that enables businesses to send physical postcards and letters programmatically
  via a REST API. The platform lets developers create campaigns, upload recipient lists, trigger individual mail pieces in
  real time, and track print and delivery status through webhooks and event endpoints. Authentication uses API key-based HTTP
  Basic Auth over HTTPS, and the API follows a simple JSON response envelope with success/data or success/error fields. Stannp
  serves businesses across the UK, US, and Canada with per-item pricing for letters and postcards at scale, and supports no-code
  integrations through Zapier and Make as well as official SDKs for PHP, Go, and C#.

  '
type: Index
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/stannp.png
tags:
- Direct Mail
- Postcards
- Letters
- Print
- Physical Mail
- Marketing Automation
- Campaigns
- Address Verification
- SMS
- Webhook
- Mailing Lists
- Fulfillment
tags_raw:
- Direct Mail
- Postcards
- Letters
- Print
- Physical Mail
- Marketing Automation
- Campaigns
- Address Verification
- SMS
- Webhooks
- Mailing Lists
- Fulfillment
url: https://raw.githubusercontent.com/api-evangelist/stannp/refs/heads/main/apis.yml
created: '2026-06-12'
modified: '2026-08-13'
specificationVersion: '0.23'
apis:
- aid: stannp:stannp-account-api
  name: Stannp Account API
  description: Account balance and user information
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Account
  properties:
  - type: OpenAPI
    url: openapi/stannp-account-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-account-api-overlay.yaml
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-campaigns-api
  name: Stannp Campaigns API
  description: Manage batch direct mail campaigns
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Campaigns
  properties:
  - type: OpenAPI
    url: openapi/stannp-campaigns-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-campaigns-api-overlay.yaml
  - type: AgentSkill
    url: skills/stannp-build-and-book-a-campaign.md
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-events-api
  name: Stannp Events API
  description: Record recipient engagement and conversion events
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/stannp-events-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-events-api-overlay.yaml
  - type: Webhooks
    url: asyncapi/stannp-webhooks.yml
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-groups-api
  name: Stannp Groups API
  description: Manage recipient groups
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Group
  tags_raw:
  - Groups
  properties:
  - type: OpenAPI
    url: openapi/stannp-groups-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-groups-api-overlay.yaml
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-letters-api
  name: Stannp Letters API
  description: Create, post, retrieve, and cancel letter mailpieces
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Letters
  properties:
  - type: OpenAPI
    url: openapi/stannp-letters-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-letters-api-overlay.yaml
  - type: AgentSkill
    url: skills/stannp-send-a-transactional-letter.md
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-postcards-api
  name: Stannp Postcards API
  description: Create, retrieve, and cancel postcard mailpieces
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Postcards
  properties:
  - type: OpenAPI
    url: openapi/stannp-postcards-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-postcards-api-overlay.yaml
  - type: AgentSkill
    url: skills/stannp-send-a-single-postcard.md
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
- aid: stannp:stannp-recipients-api
  name: Stannp Recipients API
  description: Manage individual recipients and bulk imports
  humanURL: https://www.stannp.com/us/direct-mail-api
  baseURL: https://api-eu1.stannp.com/v1/
  tags:
  - Recipients
  properties:
  - type: OpenAPI
    url: openapi/stannp-recipients-api-openapi.yml
  - type: Overlay
    url: overlays/stannp-recipients-api-overlay.yaml
  - type: AgentSkill
    url: skills/stannp-sync-recipients-and-track-engagement.md
  - type: Documentation
    url: https://www.stannp.com/us/direct-mail-api/guide
  - type: JSONSchema
    url: json-schema/recipient.json
  - type: JSONSchema
    url: json-schema/mailpiece.json
  - type: JSONSchema
    url: json-schema/campaign.json
  - type: Vocabulary
    url: vocabulary/stannp-vocabulary.yml
  - type: JSONLDContext
    url: json-ld/stannp-context.jsonld
common:
- type: AgenticAccess
  url: agentic-access/stannp-agentic-access.yml
- type: TrustCenter
  url: security/stannp-trust-center.yml
- type: Compliance
  url: https://www.stannp.com/us/accreditations
- type: DomainSecurity
  url: security/stannp-domain-security.yml
- type: VulnerabilityDisclosure
  url: security/stannp-vulnerability-disclosure.yml
- type: Security
  url: https://www.stannp.com/us/trust
- type: Authentication
  url: authentication/stannp-authentication.yml
- type: Conventions
  url: conventions/stannp-conventions.yml
- type: Idempotency
  url: conventions/stannp-conventions.yml
- type: ErrorCatalog
  url: errors/stannp-problem-types.yml
- type: DataModel
  url: data-model/stannp-data-model.yml
- type: Conformance
  url: conformance/stannp-conformance.yml
- type: Lifecycle
  url: lifecycle/stannp-lifecycle.yml
- type: StatusPage
  url: https://status.stannp.com/
- type: Sandbox
  url: sandbox/stannp-sandbox.yml
- type: Webhooks
  url: asyncapi/stannp-webhooks.yml
- type: Packages
  url: packages/stannp-packages.yml
- type: SDKs
  url: packages/stannp-packages.yml
- type: MCPServer
  url: mcp/stannp-mcp.yml
- type: AgentSkill
  url: skills/_index.yml
- type: LLMsTxt
  url: llms/stannp-llms.txt
- type: Website
  url: https://www.stannp.com
- type: DeveloperPortal
  url: https://www.stannp.com/us/developer-tools
- type: Documentation
  url: https://www.stannp.com/us/direct-mail-api/guide
- type: APIReference
  url: https://www.stannp.com/us/direct-mail-api/postcards
- type: GettingStarted
  url: https://www.stannp.com/us/direct-mail-api/guide#introduction
- type: Support
  url: https://www.stannp.com/us/support
- type: HelpCenter
  url: https://knowledge.stannp.com/us
- type: Integrations
  url: https://www.stannp.com/us/integrations
- type: GitHubOrganization
  url: https://github.com/Stannp
- type: LinkedIn
  url: https://www.linkedin.com/company/stannp-com-postcard-bulk-mailer
- type: X
  url: https://twitter.com/stannpdm
- type: Blog
  url: https://go.stannp.com/en-us/blogs
- type: Pricing
  url: https://www.stannp.com/us/pricing
- type: Plans
  url: plans/stannp-plans-pricing.yml
- type: SignUp
  url: https://app-us1.stannp.com/register
- type: Login
  url: https://app-us1.stannp.com/login
- type: TermsOfService
  url: https://www.stannp.com/us/terms-of-service
- type: PrivacyPolicy
  url: https://www.stannp.com/us/privacy-policy
- type: RateLimits
  url: rate-limits/stannp-rate-limits.yml
- type: FinOps
  url: finops/stannp-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 25
  pass: local-v1

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
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 provider

curl "https://apis.io/api/v1/providers/stannp"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/stannp/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/stannp/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no email required.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.