listmonk

listmonk is a free and open-source, self-hosted newsletter and mailing-list manager built in Go with a Vue front end. Every feature in the admin UI is backed by a documented REST API on the self-hosted instance (Basic auth with an API user and token) covering subscribers, lists, campaigns, templates, media, CSV import, transactional messages, and bounces. There is no hosted SaaS - users run their own instance.

listmonk publishes 14 APIs on the APIs.io network, including Bounces API, Campaigns API, Import API, and 11 more. Tagged areas include Email, Newsletter, Mailing List, Marketing, and Transactional Email.

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

listmonk’s developer surface includes authentication, documentation, changelog, CLI, sandbox, API reference, getting-started guide, and 28 more developer resources.

🌐 Visit website 📡 Source on GitHub

48.0/100 developing ▬ flat Agent 32/100 agent ready Full breakdown ↓
scored 2026-09-14 · rubric v0.22.0

AccessFreemiumSelf serve⚡ Free to try

2 APIs

Email NewsletterMailing ListMarketing Transactional Email Campaigns SubscribersBounce HandlingOpen-Source Self-Hosted Go PostgreSQL

Kin Score

Kin Score How this is scored →
scored 2026-09-14 · rubric v0.22.0

Composite quality — 48.0/100 · developing

Contract Quality 9.1 / 19

Developer Ergonomics 10.6 / 15

Access Clarity 4.3 / 15

Operational Transparency 6.7 / 10

Contract Governance 0.4 / 9

Discoverability 5.1 / 8

Regulatory Posture 4.8 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 32/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 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 Well-Known Document 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.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% 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/. 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 github.com/api-evangelist/listmonk: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 1

Interfaces this provider implements that became standards by being copied rather than ratified. Each is profiled by the API Commons, and the evidence column says how the claim was established — not that it was made.

The S3 Interface

prose — states compatibility; nothing published to check it against

8 core of 116 operations graded · api-commons/storage

APIs 14

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

listmonk Bounces API

The Bounces API from listmonk — 2 operation(s) for bounces.

listmonk Campaigns API

The Campaigns API from listmonk — 8 operation(s) for campaigns.

listmonk Import API

The Import API from listmonk — 2 operation(s) for import.

listmonk Lists API

The Lists API from listmonk — 3 operation(s) for lists.

listmonk Media API

The Media API from listmonk — 2 operation(s) for media.

listmonk Subscribers API

The Subscribers API from listmonk — 10 operation(s) for subscribers.

listmonk Templates API

The Templates API from listmonk — 5 operation(s) for templates.

listmonk Transactional API

The Transactional API from listmonk — 1 operation(s) for transactional.

listmonk Admin API

Admin API

listmonk Logs API

Logs API

listmonk Maintenance API

Maintenance API

listmonk Miscellaneous API

Misc API

listmonk Public API

Listmonk Public API

listmonk Settings API

Settings API

Scroll for all 14

Open Collections 10

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

listmonk Bounces API

OPEN COLLECTION

listmonk Bounces Campaigns API

OPEN COLLECTION

listmonk Bounces Import API

OPEN COLLECTION

listmonk Bounces Lists API

OPEN COLLECTION

listmonk Bounces Media API

OPEN COLLECTION

listmonk Bounces Subscribers API

OPEN COLLECTION

listmonk Bounces Templates API

OPEN COLLECTION

listmonk Bounces Transactional API

OPEN COLLECTION

listmonk API

OPEN COLLECTION

Scroll for all 10

Pricing Plans 1

Published pricing tiers and plan structures.

Listmonk Plans Pricing

1 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Listmonk Rate Limits

4 limits

RATE LIMITS

FinOps 1

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

Listmonk Finops

FINOPS

Event Specifications 1

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

listmonk Bounce Webhooks

listmonk's event surface is INGRESS, not egress: a listmonk instance receives bounce and complaint events, it does not emit webhooks to subscribers of its own. This document mod...

ASYNCAPI

Security Posture 3

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

Listmonk Authentication

http/apiKey · 2 schemes

SECURITY

Listmonk Domain Security

TLSv1.3

SECURITY

Listmonk Vulnerability Disclosure

disclosure policy published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Listmonk Agentic Access

53 operations · 34 acting · 1 human-in-the-loop

53 operations · 34 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

Sandbox

DeveloperPortal

GettingStarted

Demo

Documentation 4

Reference material describing how the API behaves

Documentation

OpenAPI

AsyncAPI

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

LLMsTxt

LLMsTxt

AgentSkill

AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Webhooks

Conventions

ErrorCatalog

DataModel

Conformance

Lifecycle

Build 5

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

ToolCrosswalk

CLI

SourceCode

Access & Security 4

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

Operate 3

Status, limits, changes, and where to get help

RateLimits

RateLimits

ChangeLog

ChangeLog

Support

Support

Commercial 3

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

License

License

Company 2

The organization behind the API

LinkedIn

Website

Website

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: listmonk
url: https://raw.githubusercontent.com/api-evangelist/listmonk/refs/heads/main/apis.yml
name: listmonk
kind: company
description: listmonk is a free and open-source, self-hosted newsletter and mailing-list manager built in Go with a Vue front
  end. Every feature in the admin UI is backed by a documented REST API on the self-hosted instance (Basic auth with an API
  user and token) covering subscribers, lists, campaigns, templates, media, CSV import, transactional messages, and bounces.
  There is no hosted SaaS - users run their own instance.
deliveryModel:
  model: unknown
  open_source: unknown
  commercial: true
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - openapi
  - pricing
  - repository-unlicensed
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  - rate-limits
  - security
  - sandbox
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/listmonk.png
tags:
- Email
- Newsletter
- Mailing List
- Marketing
- Transactional Email
- Campaigns
- Subscribers
- Bounce Handling
- Open-Source
- Self-Hosted
- Go
- PostgreSQL
tags_raw:
- Email
- Newsletter
- Mailing List
- Marketing
- Transactional Email
- Campaigns
- Subscribers
- Bounce Handling
- Open Source
- Self-Hosted
- Go
- PostgreSQL
created: '2026-06-25'
modified: '2026-08-13'
specificationVersion: '0.23'
apis:
- aid: listmonk:listmonk-bounces-api
  name: listmonk Bounces API
  description: The Bounces API from listmonk — 2 operation(s) for bounces.
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Bounces
  properties:
  - type: OpenAPI
    url: openapi/listmonk-bounces-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/bounces/
- aid: listmonk:listmonk-campaigns-api
  name: listmonk Campaigns API
  description: The Campaigns API from listmonk — 8 operation(s) for campaigns.
  humanURL: https://listmonk.app/docs/apis/campaigns/
  baseURL: https://{listmonk_host}/api
  tags:
  - Campaigns
  properties:
  - type: OpenAPI
    url: openapi/listmonk-campaigns-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/campaigns/
- aid: listmonk:listmonk-import-api
  name: listmonk Import API
  description: The Import API from listmonk — 2 operation(s) for import.
  humanURL: https://listmonk.app/docs/apis/import/
  baseURL: https://{listmonk_host}/api
  tags:
  - Import
  properties:
  - type: OpenAPI
    url: openapi/listmonk-import-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/import/
- aid: listmonk:listmonk-lists-api
  name: listmonk Lists API
  description: The Lists API from listmonk — 3 operation(s) for lists.
  humanURL: https://listmonk.app/docs/apis/lists/
  baseURL: https://{listmonk_host}/api
  tags:
  - List
  tags_raw:
  - Lists
  properties:
  - type: OpenAPI
    url: openapi/listmonk-lists-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/lists/
- aid: listmonk:listmonk-media-api
  name: listmonk Media API
  description: The Media API from listmonk — 2 operation(s) for media.
  humanURL: https://listmonk.app/docs/apis/media/
  baseURL: https://{listmonk_host}/api
  tags:
  - Media
  properties:
  - type: OpenAPI
    url: openapi/listmonk-media-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/media/
- aid: listmonk:listmonk-subscribers-api
  name: listmonk Subscribers API
  description: The Subscribers API from listmonk — 10 operation(s) for subscribers.
  humanURL: https://listmonk.app/docs/apis/subscribers/
  baseURL: https://{listmonk_host}/api
  tags:
  - Subscribers
  properties:
  - type: OpenAPI
    url: openapi/listmonk-subscribers-api-openapi.yml
  - type: Documentation
    url: https://listmonk.app/docs/apis/subscribers/
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
- aid: listmonk:listmonk-templates-api
  name: listmonk Templates API
  description: The Templates API from listmonk — 5 operation(s) for templates.
  humanURL: https://listmonk.app/docs/apis/templates/
  baseURL: https://{listmonk_host}/api
  tags:
  - Templates
  properties:
  - type: OpenAPI
    url: openapi/listmonk-templates-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/templates/
- aid: listmonk:listmonk-transactional-api
  name: listmonk Transactional API
  description: The Transactional API from listmonk — 1 operation(s) for transactional.
  humanURL: https://listmonk.app/docs/apis/transactional/
  baseURL: https://{listmonk_host}/api
  tags:
  - Transactional
  properties:
  - type: OpenAPI
    url: openapi/listmonk-transactional-api-openapi.yml
  - type: APIReference
    url: https://listmonk.app/docs/apis/apis/
  - type: Documentation
    url: https://listmonk.app/docs/apis/transactional/
- aid: listmonk:listmonk-admin-api
  name: listmonk Admin API
  description: Admin API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Admin
  properties:
  - type: OpenAPI
    url: openapi/listmonk-admin-api-openapi.yml
- aid: listmonk:listmonk-logs-api
  name: listmonk Logs API
  description: Logs API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Logs
  properties:
  - type: OpenAPI
    url: openapi/listmonk-logs-api-openapi.yml
- aid: listmonk:listmonk-maintenance-api
  name: listmonk Maintenance API
  description: Maintenance API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Maintenance
  properties:
  - type: OpenAPI
    url: openapi/listmonk-maintenance-api-openapi.yml
- aid: listmonk:listmonk-miscellaneous-api
  name: listmonk Miscellaneous API
  description: Misc API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags: []
  tags_raw:
  - Miscellaneous
  properties:
  - type: OpenAPI
    url: openapi/listmonk-miscellaneous-api-openapi.yml
- aid: listmonk:listmonk-public-api
  name: listmonk Public API
  description: Listmonk Public API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Public
  properties:
  - type: OpenAPI
    url: openapi/listmonk-public-api-openapi.yml
- aid: listmonk:listmonk-settings-api
  name: listmonk Settings API
  description: Settings API
  humanURL: https://listmonk.app/docs/apis/bounces/
  baseURL: https://{listmonk_host}/api
  tags:
  - Settings
  properties:
  - type: OpenAPI
    url: openapi/listmonk-settings-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/listmonk-agentic-access.yml
- type: DomainSecurity
  url: security/listmonk-domain-security.yml
- type: Authentication
  url: authentication/listmonk-authentication.yml
- type: GitHubOrganization
  url: https://github.com/knadh/listmonk
- type: LinkedIn
  url: https://www.linkedin.com/in/knadh
- type: Website
  url: https://listmonk.app
- type: Documentation
  url: https://listmonk.app/docs/apis/apis/
- type: Plans
  url: plans/listmonk-plans-pricing.yml
- type: RateLimits
  url: rate-limits/listmonk-rate-limits.yml
- type: FinOps
  url: finops/listmonk-finops.yml
- type: OpenAPI
  url: openapi/_original/listmonk-collections-openapi.yml
- type: Overlay
  url: overlays/listmonk-collections-overlay.yaml
- type: Packages
  url: packages/listmonk-packages.yml
- type: LLMsTxt
  url: llms/listmonk-llms.txt
- type: AgentSkill
  url: skills/_index.yml
- type: ToolCrosswalk
  url: mcp/listmonk-tool-crosswalk.yml
- type: AsyncAPI
  url: asyncapi/listmonk-bounce-webhooks-asyncapi.yml
- type: Webhooks
  url: asyncapi/listmonk-bounce-webhooks-asyncapi.yml
- type: Conventions
  url: conventions/listmonk-conventions.yml
- type: ErrorCatalog
  url: errors/listmonk-problem-types.yml
- type: DataModel
  url: data-model/listmonk-data-model.yml
- type: Conformance
  url: conformance/listmonk-conformance.yml
- type: Lifecycle
  url: lifecycle/listmonk-lifecycle.yml
- type: ChangeLog
  url: changelog/listmonk-changelog.yml
- type: CLI
  url: cli/listmonk-cli.yml
- type: Sandbox
  url: sandbox/listmonk-sandbox.yml
- type: VulnerabilityDisclosure
  url: security/listmonk-vulnerability-disclosure.yml
- type: Security
  url: https://listmonk.app/docs/security-reports/
- type: DeveloperPortal
  url: https://listmonk.app/docs/
- type: APIReference
  url: https://listmonk.app/docs/apis/apis/
- type: GettingStarted
  url: https://listmonk.app/docs/installation/
- type: Support
  url: https://github.com/knadh/listmonk/issues
- type: SourceCode
  url: https://github.com/knadh/listmonk
- type: License
  url: https://github.com/knadh/listmonk/blob/master/LICENSE
- type: Demo
  url: https://demo.listmonk.app/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 18
  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/listmonk"

All providers

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

Every operation they expose

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

How their score was established

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

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

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

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