Apache Pulsar

Apache Pulsar is a cloud-native, distributed messaging and streaming platform that provides server-to-server messaging with multi-tenancy, high performance, and geo-replication. It combines messaging and stream processing in a single platform.

Apache Pulsar publishes 8 API contracts indexed on the APIs.io network, including Messaging API, Brokers API, Clusters API, and 5 more. Tagged areas include Cloud-Native, Messaging, Multi-Tenant, Pub/Sub, and Streaming.

The Apache Pulsar catalog on APIs.io includes 1 event-driven AsyncAPI specification, 1 JSON-LD context, and 3 Spectral governance rulesets.

Apache Pulsar’s developer surface includes documentation, engineering blog, and 11 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

30.9/100 thin ▬ flat Agent 18/100 agent aware Heartbeat 100/100 alive Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemium

1 published contract 7 Features 4 Use Cases

Cloud-Native Messaging Multi-Tenant Pub/Sub Streaming Apache Open Source Real-Time

Kin Score

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

Composite quality — 30.9/100 · thin

Contract Quality 10.1 / 19

Developer Ergonomics 1.8 / 15

Access Clarity 1.2 / 15

Operational Transparency 2.1 / 10

Contract Governance 2.5 / 9

Discoverability 4.3 / 8

Regulatory Posture 2.5 / 15

Create-or-Update Ergonomics 2.2 / 10

Agent readiness — 18/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 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 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 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 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/.

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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
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
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link

10 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 7.9 — up to +18.4 composite points
Developer Ergonomics scores 11.9 — up to +17.6 composite points
Contract Quality scores 53.9 — up to +11.5 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/apache-pulsar/apis.yml: open an issue on github.com/api-evangelist/apache-pulsar 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 →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Streaming (Apache Kafka protocol)	undeclared	-	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 3

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Pub/Sub

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

OpenAPI

measured — observed by APIs.io (published)

AsyncAPI

measured — observed by APIs.io (published)

APIs 8

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

Apache Pulsar Messaging API

Pulsar messaging protocol for producing and consuming messages on topics, with support for multiple subscription types (Exclusive, Shared, Failover, Key_Shared), schema enforcem...

Apache Pulsar Brokers API

The Brokers API from Apache Pulsar — 2 operation(s) for brokers.

Apache Pulsar Clusters API

The Clusters API from Apache Pulsar — 2 operation(s) for clusters.

Apache Pulsar Functions API

The Functions API from Apache Pulsar — 3 operation(s) for functions.

Apache Pulsar Namespaces API

The Namespaces API from Apache Pulsar — 3 operation(s) for namespaces.

Apache Pulsar Subscriptions API

The Subscriptions API from Apache Pulsar — 2 operation(s) for subscriptions.

Apache Pulsar Tenants API

The Tenants API from Apache Pulsar — 2 operation(s) for tenants.

Apache Pulsar Topics API

The Topics API from Apache Pulsar — 4 operation(s) for topics.

Scroll for all 8

Apache Pulsar Admin REST API

OPEN COLLECTION

Scroll for all 8

Apache Pulsar API pricing

Not yet checked against Apache Pulsar'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 Apache Pulsar's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Apache Pulsar Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Apache Pulsar Rate Limits

5 limits

RATE LIMITS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

Apache Pulsar

SLA

FinOps 1

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

Apache Pulsar Finops

FINOPS

Features 7

Notable capabilities this provider offers.

Multi-Tenancy

Native multi-tenancy with tenant and namespace isolation

Persistent Messaging

Durable message storage with Apache BookKeeper

Geo-Replication

Built-in geo-replication across data centers and clouds

Pulsar Functions

Lightweight serverless compute natively integrated with messaging

Tiered Storage

Offload old data to object storage (S3, GCS) for cost efficiency

Schema Registry

Built-in schema registry for producers and consumers

Multiple Subscription Types

Exclusive, Shared, Failover, and Key_Shared subscription modes

Scroll for all 7

Event Specifications 1

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

Apache Pulsar Messaging API

Apache Pulsar is a cloud-native, multi-tenant, high-performance messaging and streaming platform. This spec describes the messaging patterns for producing and consuming messages...

ASYNCAPI

Semantic Vocabularies 1

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

Apache Pulsar Context

7 classes · 51 properties

JSON-LD

Spectral Rules 3

Spectral governance rulesets for linting and validating these APIs.

Apache Pulsar — asyncapi rules

3 rules · 3 warnings

SPECTRAL

Apache Pulsar — jsonschema rules

5 rules · 3 warnings 2 info

SPECTRAL

Apache Pulsar API Rules

6 rules · 5 warnings 1 info

SPECTRAL

JSON Schema 8

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

ClusterData

Security Posture 2

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

Apache Pulsar Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Apache Pulsar Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

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

Apache Pulsar Agentic Access

29 operations · 13 acting

AGENTIC

Use Cases 4

What developers build with this provider.

Real-Time Event Streaming

Stream events between microservices with guaranteed delivery

Message Queue

Use Shared subscription as a traditional message queue

Event Sourcing

Store and replay event streams for event-driven architectures

IoT Data Ingestion

Ingest high-volume IoT telemetry into Pulsar topics

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Design & Contract 3

Pagination, idempotency, versioning, errors, and events

SpectralRules

SpectralRules

Vocabulary

Vocabulary

JSONLD

JSONLD

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

RateLimits

RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: apache-pulsar
name: Apache Pulsar
description: Apache Pulsar is a cloud-native, distributed messaging and streaming platform that provides server-to-server
  messaging with multi-tenancy, high performance, and geo-replication. It combines messaging and stream processing in a single
  platform.
type: Index
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - openapi
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: low
  try_now_blocked_by: loopback
  source:
  - plans
  - security
  generated: '2026-11-06'
  method: derived
position: Consuming
access: 3rd-Party
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/apache-pulsar.png
x-docs-platform: docusaurus
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-09-19
tags:
- Cloud-Native
- Messaging
- Multi-Tenant
- Pub/Sub
- Streaming
- Apache
- Open Source
- Real-Time
tags_raw:
- Cloud Native
- Messaging
- Multi-Tenant
- Pub-Sub
- Streaming
- Apache
- Open Source
- Open-Source
- Real-Time
created: '2026-03-16'
modified: '2026-05-19'
url: https://raw.githubusercontent.com/api-evangelist/apache-pulsar/refs/heads/main/apis.yml
specificationVersion: '0.23'
apis:
- aid: apache-pulsar:apache-pulsar-messaging-api
  name: Apache Pulsar Messaging API
  description: Pulsar messaging protocol for producing and consuming messages on topics, with support for multiple subscription
    types (Exclusive, Shared, Failover, Key_Shared), schema enforcement, and both persistent and non-persistent topics.
  humanURL: https://pulsar.apache.org/docs/next/client-libraries/
  tags:
  - Messaging
  - Pub/Sub
  - Streaming
  tags_raw:
  - Messaging
  - Pub-Sub
  - Streaming
  properties:
  - type: Documentation
    url: https://pulsar.apache.org/docs/next/client-libraries/
  - type: AsyncAPI
    url: asyncapi/pulsar-messaging.yml
  - type: JSONSchema
    url: json-schema/pulsar-message.json
- aid: apache-pulsar:apache-pulsar-brokers-api
  name: Apache Pulsar Brokers API
  description: The Brokers API from Apache Pulsar — 2 operation(s) for brokers.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Brokerage
  tags_raw:
  - Brokers
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-brokers-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-clusters-api
  name: Apache Pulsar Clusters API
  description: The Clusters API from Apache Pulsar — 2 operation(s) for clusters.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Cluster
  tags_raw:
  - Clusters
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-clusters-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-functions-api
  name: Apache Pulsar Functions API
  description: The Functions API from Apache Pulsar — 3 operation(s) for functions.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Functions
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-functions-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-namespaces-api
  name: Apache Pulsar Namespaces API
  description: The Namespaces API from Apache Pulsar — 3 operation(s) for namespaces.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Namespaces
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-namespaces-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-subscriptions-api
  name: Apache Pulsar Subscriptions API
  description: The Subscriptions API from Apache Pulsar — 2 operation(s) for subscriptions.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Subscription
  tags_raw:
  - Subscriptions
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-subscriptions-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-tenants-api
  name: Apache Pulsar Tenants API
  description: The Tenants API from Apache Pulsar — 2 operation(s) for tenants.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Tenants
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-tenants-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
- aid: apache-pulsar:apache-pulsar-topics-api
  name: Apache Pulsar Topics API
  description: The Topics API from Apache Pulsar — 4 operation(s) for topics.
  humanURL: https://pulsar.apache.org/admin-rest-api/
  baseURL: http://localhost:8080/admin/v2
  tags:
  - Topic
  tags_raw:
  - Topics
  properties:
  - type: OpenAPI
    url: openapi/apache-pulsar-topics-api-openapi.yml
  - type: Documentation
    url: https://pulsar.apache.org/admin-rest-api/
integrations:
- name: Apache Pulsar
- name: Slack
- name: GitHub
- name: Pulsar
maintainers:
- FN: Kin Lane
  email: info@apievangelist.com
common:
- type: Plans
  url: plans/apache-pulsar-plans-pricing.yml
- type: RateLimits
  url: rate-limits/apache-pulsar-rate-limits.yml
- type: FinOps
  url: finops/apache-pulsar-finops.yml
- type: Website
  url: https://www.apache.org/
- type: AgenticAccess
  url: agentic-access/apache-pulsar-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/apache-pulsar-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/apache-pulsar-domain-security.yml
- type: GitHubOrganization
  url: https://github.com/apache/pulsar
- type: Documentation
  url: https://pulsar.apache.org/
- type: SpectralRules
  url: rules/apache-pulsar-spectral-rules.yml
- type: Vocabulary
  url: vocabulary/apache-pulsar-vocabulary.yaml
- type: JSONLD
  url: json-ld/apache-pulsar-context.jsonld
- type: Blog
  url: https://pulsar.apache.org/blog/rss.xml
- type: Features
  data:
  - name: Multi-Tenancy
    description: Native multi-tenancy with tenant and namespace isolation
  - name: Persistent Messaging
    description: Durable message storage with Apache BookKeeper
  - name: Geo-Replication
    description: Built-in geo-replication across data centers and clouds
  - name: Pulsar Functions
    description: Lightweight serverless compute natively integrated with messaging
  - name: Tiered Storage
    description: Offload old data to object storage (S3, GCS) for cost efficiency
  - name: Schema Registry
    description: Built-in schema registry for producers and consumers
  - name: Multiple Subscription Types
    description: Exclusive, Shared, Failover, and Key_Shared subscription modes
- type: UseCases
  data:
  - name: Real-Time Event Streaming
    description: Stream events between microservices with guaranteed delivery
  - name: Message Queue
    description: Use Shared subscription as a traditional message queue
  - name: Event Sourcing
    description: Store and replay event streams for event-driven architectures
  - name: IoT Data Ingestion
    description: Ingest high-volume IoT telemetry into Pulsar topics
- type: Integrations
  data:
  - name: Apache Flink
    description: Pulsar connector for Flink stream processing
  - name: Apache Spark
    description: Spark Streaming integration via Pulsar connector
  - name: Apache Kafka
    description: Kafka-compatible protocol support for migration
  - name: Kubernetes
    description: Native Kubernetes deployment via Helm charts
  - name: Grafana
    description: Built-in metrics exposed to Prometheus and Grafana
- type: Integrations
  url: https://pulsar.apache.org/ecosystem/

Apache Pulsar API — frequently asked questions

Does Apache Pulsar have an API?

Yes. APIs.io lists 8 APIs from Apache Pulsar, including Apache Pulsar Messaging API, Apache Pulsar Brokers API and Apache Pulsar Clusters API, and 5 more.

Is there an OpenAPI specification for the Apache Pulsar API?

Yes. APIs.io indexes 7 OpenAPI specifications for Apache Pulsar, each linked for download from this page.

How much does the Apache Pulsar API cost?

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

Is the Apache Pulsar API ready for AI agents?

Apache Pulsar has a Kin Score of 30.9 out of 100 (thin) and an Agent Readiness score of 17.6 (agent-aware), scored by API Evangelist on 2026-11-06.

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