MassTransit

MassTransit is a free, open source distributed application framework for .NET that makes it easy to create applications and services that leverage message-based, loosely-coupled asynchronous communication for higher availability, reliability, and scalability.

MassTransit is listed with 1 API on the APIs.io network. Tagged areas include .NET, Event-Driven, Message Bus, Messaging, and Open Source.

The MassTransit catalog on APIs.io includes 1 Spectral governance ruleset.

MassTransit’s developer surface includes documentation, getting-started guide, GitHub presence, and 7 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

17.0/100 emerging ▬ flat Agent 1/100 human only Front door AI 1/6 silent Heartbeat 94/100 alive self hosted · Apache-2.0 Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemium

1 API

.NET Event-DrivenMessage BusMessaging Open SourceSagas

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 17.0/100 · emerging

Contract Quality 2.6 / 21

Developer Ergonomics 4.5 / 17

Access Clarity 1.3 / 17

Operational Transparency 1.5 / 11

Contract Governance 1.0 / 10

Discoverability 4.9 / 9

Regulatory Posture 0.9 / 15

Agent readiness — 1/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 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

MCP Tool Quality 6 / 6

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):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
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
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes

12 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 12.0 — up to +22.0 composite points
Access Clarity scores 7.9 — up to +18.4 composite points
Developer Ergonomics scores 26.2 — up to +14.8 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/masstransit/apis.yml: open an issue on github.com/api-evangelist/masstransit 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.

MassTransit Messaging Framework

MassTransit provides a consistent abstraction on top of message transports like RabbitMQ, Azure Service Bus, and Amazon SQS, with support for sagas, state machines, routing slip...

MassTransit API pricing

Not yet checked against MassTransit's own pricing page. Compiled by API Evangelist on 2026-05-04; confirm before you rely on a figure. A free plan or tier is listed.

Plan	Price
Free freemium	Free
Professional paid	Free
Enterprise enterprise	—

Plan details, limits and sources →

Rate limits

Free Tier Default: 10 requests per minute
Free Tier Monthly Quota: 1000 requests per month
Professional Tier Default: 100 requests per minute

Compiled by API Evangelist, not yet checked against MassTransit's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Masstransit Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Masstransit Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Masstransit Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

MassTransit — jsonschema rules

5 rules · 3 warnings 2 info

SPECTRAL

JSON Schema 2

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

MassTransit Message Envelope

15 properties

JSON SCHEMA

MassTransit Saga State

8 properties

JSON SCHEMA

Security Posture 1

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

Masstransit Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Build 1

SDKs, sample code, and the tooling you integrate with

GitHub

GitHub

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

Discord

Discord

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

Company 1

The organization behind the API

Website

Website

Other 1

Properties that don't map to a standard resource type

NuGet

NuGet

Source (apis.yml)

aid: masstransit
name: MassTransit
description: MassTransit is a free, open source distributed application framework for .NET that makes it easy to create applications
  and services that leverage message-based, loosely-coupled asynchronous communication for higher availability, reliability,
  and scalability.
type: Index
deliveryModel:
  model: self-hosted
  license: Apache-2.0
  license_evidence:
    repo: masstransit/masstransit
    spdx: Apache-2.0
    stars: 7803
  open_source: true
  commercial: false
  callable_host: false
  label: Self-hosted open source · you run it yourself
  confidence: medium
  source:
  - repository-license
  generated: '2026-09-25'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: low
  source:
  - plans
  - security
  - url: https://masstransit.io/
    status: 307
    note: declared website redirects to https://masstransit.massient.com/ — a different registrable domain (masstransit.io
      -> massient.com), possible rename or acquisition (probed 2026-09-03, roadmap#169)
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/masstransit.png
tags:
- .NET
- Event-Driven
- Message Bus
- Messaging
- Open Source
- Sagas
tags_raw:
- .NET
- Event-Driven
- Message Bus
- Messaging
- Open Source
- Sagas
- Open-Source
url: https://raw.githubusercontent.com/api-evangelist/masstransit/refs/heads/main/apis.yml
created: '2026-03-26'
modified: '2026-04-28'
specificationVersion: '0.23'
apis:
- aid: masstransit:masstransit-messaging
  name: MassTransit Messaging Framework
  description: MassTransit provides a consistent abstraction on top of message transports like RabbitMQ, Azure Service Bus,
    and Amazon SQS, with support for sagas, state machines, routing slip activities, and a standardized message envelope format.
  humanURL: https://masstransit.io/
  tags:
  - .NET
  - Event-Driven
  - Message Bus
  - Messaging
  - Sagas
  properties:
  - type: Documentation
    url: https://masstransit.io/documentation/concepts
  - type: JSONSchema
    url: json-schema/masstransit-message-envelope.json
  - type: JSONSchema
    url: json-schema/masstransit-saga-state.json
common:
- type: Plans
  url: plans/masstransit-plans-pricing.yml
- type: RateLimits
  url: rate-limits/masstransit-rate-limits.yml
- type: FinOps
  url: finops/masstransit-finops.yml
- type: DomainSecurity
  url: security/masstransit-domain-security.yml
- type: Website
  url: https://masstransit.io/
- type: Documentation
  url: https://masstransit.io/documentation/concepts
- type: GettingStarted
  url: https://masstransit.io/quick-starts
- type: GitHub
  url: https://github.com/MassTransit/MassTransit
- type: Discord
  url: https://discord.gg/rNpQgYn
- type: NuGet
  url: https://www.nuget.org/packages/MassTransit
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

MassTransit API — frequently asked questions

Does MassTransit have an API?

Yes. APIs.io lists 1 API from MassTransit, including MassTransit Messaging Framework.

How much does the MassTransit API cost?

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

Is the MassTransit API ready for AI agents?

MassTransit has a Kin Score of 17.0 out of 100 (emerging) and an Agent Readiness score of 0.6 (human-only), scored by API Evangelist on 2026-11-06.

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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.

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