Apache OpenNLP

Apache OpenNLP is a machine learning based toolkit for the processing of natural language text. It supports common NLP tasks such as tokenization, sentence segmentation, part-of-speech tagging, named entity extraction, chunking, parsing, and coreference resolution.

Apache OpenNLP is listed with 10 APIs on the APIs.io network, including Chunking API, Document Categorization API, Language Detection API, and 7 more. Tagged areas include Machine Learning, Natural Language Processing, Text Processing, Apache, and Open Source.

The Apache OpenNLP catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Apache OpenNLP’s developer surface includes documentation, getting-started guide, engineering blog, and 11 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

22.7/100 emerging ▬ flat Agent 17/100 agent aware Heartbeat 77/100 alive Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemium

10 APIs 10 Features 5 Use Cases

Machine Learning Natural Language Processing Text Processing Apache Open Source Java

Kin Score

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

Composite quality — 22.7/100 · emerging

Contract Quality 3.6 / 19

Developer Ergonomics 3.6 / 15

Access Clarity 1.2 / 15

Operational Transparency 2.1 / 10

Contract Governance 2.5 / 9

Discoverability 4.7 / 8

Regulatory Posture 2.3 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 17/100 · 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 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 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):

Contract Quality scores 19.1 — up to +20.2 composite points
Access Clarity scores 7.9 — up to +18.4 composite points
Developer Ergonomics scores 23.8 — up to +15.2 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-opennlp/apis.yml: open an issue on github.com/api-evangelist/apache-opennlp 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 →

Standards implemented 1

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.

OpenAPI

measured — observed by APIs.io (published)

APIs 10

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

Apache OpenNLP Chunking API

The Chunking API from Apache OpenNLP — 1 operation(s) for chunking.

Apache OpenNLP Document Categorization API

The Document Categorization API from Apache OpenNLP — 1 operation(s) for document categorization.

Apache OpenNLP Language Detection API

The Language Detection API from Apache OpenNLP — 1 operation(s) for language detection.

Apache OpenNLP Lemmatization API

The Lemmatization API from Apache OpenNLP — 1 operation(s) for lemmatization.

Apache OpenNLP Models API

The Models API from Apache OpenNLP — 2 operation(s) for models.

Apache OpenNLP Named Entity Recognition API

The Named Entity Recognition API from Apache OpenNLP — 1 operation(s) for named entity recognition.

Apache OpenNLP Parsing API

The Parsing API from Apache OpenNLP — 1 operation(s) for parsing.

Apache OpenNLP POS Tagging API

The POS Tagging API from Apache OpenNLP — 1 operation(s) for pos tagging.

Apache OpenNLP Sentence Detection API

The Sentence Detection API from Apache OpenNLP — 1 operation(s) for sentence detection.

Apache OpenNLP Tokenization API

The Tokenization API from Apache OpenNLP — 1 operation(s) for tokenization.

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Apache OpenNLP Tools Chunking Tokenization API

OPEN COLLECTION

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Apache OpenNLP API pricing

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

Pricing Plans 1

Published pricing tiers and plan structures.

Apache Opennlp Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Apache Opennlp 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 OpenNLP

SLA

FinOps 1

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

Apache Opennlp Finops

FINOPS

Features 10

Notable capabilities this provider offers.

Language Detection

Detects document language using ISO-639-3 classification

Sentence Detection

Splits text into individual sentences with character offsets

Tokenization

Segments text into words and punctuation with position tracking

Named Entity Recognition

Detects persons, locations, organizations, and other named entities

POS Tagging

Assigns Penn Treebank POS tags to each token

Lemmatization

Reduces tokens to their dictionary base forms

Chunking

Identifies noun phrases, verb phrases, and other syntactic chunks

Parsing

Builds full syntactic parse trees using constituency parsing

Document Categorization

Classifies documents into predefined categories

Custom Model Training

Train custom models with Maxent, Perceptron, or Naive Bayes algorithms

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Semantic Vocabularies 1

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

Apache Opennlp Context

18 classes · 24 properties

JSON-LD

Spectral Rules 2

Spectral governance rulesets for linting and validating these APIs.

Apache OpenNLP — jsonschema rules

5 rules · 3 warnings 2 info

SPECTRAL

Apache OpenNLP API Rules

16 rules · 5 errors 9 warnings 2 info

SPECTRAL

2 properties

JSON STRUCTURE

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2 fields

EXAMPLE

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Security Posture 2

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

Apache Opennlp Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Apache Opennlp Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

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

Apache Opennlp Agentic Access

11 operations · 8 acting

AGENTIC

Use Cases 5

What developers build with this provider.

Information Extraction

Extract structured data from unstructured text documents

Text Classification

Automatically categorize documents by topic or sentiment

Search Enhancement

Improve search relevance with NLP-based query processing

Content Analysis

Analyze large text corpora for entities, topics, and patterns

Chatbot Development

Build conversational AI with NLP intent and entity extraction

Integrations 5

Pre-built integrations with other platforms and tools.

Apache Solr

Integrate OpenNLP with Apache Solr for NLP-enhanced search

Apache Lucene

Use OpenNLP analyzers in Lucene text processing pipelines

Apache Flink

Real-time NLP processing with Apache Flink data streams

UIMA

Apache UIMA framework integration for unstructured information analysis

Maven/Gradle

Available on Maven Central for Java build system integration

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

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-opennlp
name: Apache OpenNLP
description: Apache OpenNLP is a machine learning based toolkit for the processing of natural language text. It supports common
  NLP tasks such as tokenization, sentence segmentation, part-of-speech tagging, named entity extraction, chunking, parsing,
  and coreference resolution.
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
  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-opennlp.png
tags:
- Machine Learning
- Natural Language Processing
- Text Processing
- Apache
- Open Source
- Java
tags_raw:
- Machine Learning
- Natural Language Processing
- NLP
- Text Processing
- Apache
- Open Source
- Java
- Machine-Learning
- Open-Source
created: '2026-03-16'
modified: '2026-05-19'
url: https://raw.githubusercontent.com/api-evangelist/apache-opennlp/refs/heads/main/apis.yml
specificationVersion: '0.23'
apis:
- aid: apache-opennlp:apache-opennlp-chunking-api
  name: Apache OpenNLP Chunking API
  description: The Chunking API from Apache OpenNLP — 1 operation(s) for chunking.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Chunking
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-chunking-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-document-categorization-api
  name: Apache OpenNLP Document Categorization API
  description: The Document Categorization API from Apache OpenNLP — 1 operation(s) for document categorization.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Document Categorization
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-document-categorization-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-language-detection-api
  name: Apache OpenNLP Language Detection API
  description: The Language Detection API from Apache OpenNLP — 1 operation(s) for language detection.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Language Detection
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-language-detection-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-lemmatization-api
  name: Apache OpenNLP Lemmatization API
  description: The Lemmatization API from Apache OpenNLP — 1 operation(s) for lemmatization.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Lemmatization
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-lemmatization-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-models-api
  name: Apache OpenNLP Models API
  description: The Models API from Apache OpenNLP — 2 operation(s) for models.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Models
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-models-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-named-entity-recognition-api
  name: Apache OpenNLP Named Entity Recognition API
  description: The Named Entity Recognition API from Apache OpenNLP — 1 operation(s) for named entity recognition.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Named Entity Recognition
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-named-entity-recognition-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-parsing-api
  name: Apache OpenNLP Parsing API
  description: The Parsing API from Apache OpenNLP — 1 operation(s) for parsing.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Parsing
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-parsing-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-pos-tagging-api
  name: Apache OpenNLP POS Tagging API
  description: The POS Tagging API from Apache OpenNLP — 1 operation(s) for pos tagging.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - POS Tagging
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-pos-tagging-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-sentence-detection-api
  name: Apache OpenNLP Sentence Detection API
  description: The Sentence Detection API from Apache OpenNLP — 1 operation(s) for sentence detection.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Sentence Detection
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-sentence-detection-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
- aid: apache-opennlp:apache-opennlp-tokenization-api
  name: Apache OpenNLP Tokenization API
  description: The Tokenization API from Apache OpenNLP — 1 operation(s) for tokenization.
  humanURL: https://opennlp.apache.org/docs/
  tags:
  - Tokenization
  properties:
  - type: OpenAPI
    url: openapi/apache-opennlp-tokenization-api-openapi.yml
  - type: Documentation
    url: https://opennlp.apache.org/docs/
maintainers:
- FN: Kin Lane
  email: info@apievangelist.com
common:
- type: Plans
  url: plans/apache-opennlp-plans-pricing.yml
- type: RateLimits
  url: rate-limits/apache-opennlp-rate-limits.yml
- type: FinOps
  url: finops/apache-opennlp-finops.yml
- type: Website
  url: https://www.apache.org/
- type: AgenticAccess
  url: agentic-access/apache-opennlp-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/apache-opennlp-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/apache-opennlp-domain-security.yml
- type: GitHubOrganization
  url: https://github.com/apache/opennlp
- type: Documentation
  url: https://opennlp.apache.org/
- type: GettingStarted
  url: https://opennlp.apache.org/docs/
- type: SpectralRules
  url: rules/apache-opennlp-spectral-rules.yml
- type: Vocabulary
  url: vocabulary/apache-opennlp-vocabulary.yaml
- type: JSONLD
  url: json-ld/apache-opennlp-context.jsonld
- type: Features
  data:
  - name: Language Detection
    description: Detects document language using ISO-639-3 classification
  - name: Sentence Detection
    description: Splits text into individual sentences with character offsets
  - name: Tokenization
    description: Segments text into words and punctuation with position tracking
  - name: Named Entity Recognition
    description: Detects persons, locations, organizations, and other named entities
  - name: POS Tagging
    description: Assigns Penn Treebank POS tags to each token
  - name: Lemmatization
    description: Reduces tokens to their dictionary base forms
  - name: Chunking
    description: Identifies noun phrases, verb phrases, and other syntactic chunks
  - name: Parsing
    description: Builds full syntactic parse trees using constituency parsing
  - name: Document Categorization
    description: Classifies documents into predefined categories
  - name: Custom Model Training
    description: Train custom models with Maxent, Perceptron, or Naive Bayes algorithms
- type: UseCases
  data:
  - name: Information Extraction
    description: Extract structured data from unstructured text documents
  - name: Text Classification
    description: Automatically categorize documents by topic or sentiment
  - name: Search Enhancement
    description: Improve search relevance with NLP-based query processing
  - name: Content Analysis
    description: Analyze large text corpora for entities, topics, and patterns
  - name: Chatbot Development
    description: Build conversational AI with NLP intent and entity extraction
- type: Integrations
  data:
  - name: Apache Solr
    description: Integrate OpenNLP with Apache Solr for NLP-enhanced search
  - name: Apache Lucene
    description: Use OpenNLP analyzers in Lucene text processing pipelines
  - name: Apache Flink
    description: Real-time NLP processing with Apache Flink data streams
  - name: UIMA
    description: Apache UIMA framework integration for unstructured information analysis
  - name: Maven/Gradle
    description: Available on Maven Central for Java build system integration
- url: https://opennlp.apache.org/feed.xml
  type: Blog

Apache OpenNLP API — frequently asked questions

Does Apache OpenNLP have an API?

Yes. APIs.io lists 10 APIs from Apache OpenNLP, including Apache OpenNLP Chunking API, Apache OpenNLP Document Categorization API and Apache OpenNLP Language Detection API, and 7 more.

Is there an OpenAPI specification for the Apache OpenNLP API?

Yes. APIs.io indexes 10 OpenAPI specifications for Apache OpenNLP, each linked for download from this page.

How much does the Apache OpenNLP API cost?

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

Is the Apache OpenNLP API ready for AI agents?

Apache OpenNLP has a Kin Score of 22.7 out of 100 (emerging) and an Agent Readiness score of 17.2 (agent-aware), scored by API Evangelist on 2026-11-06.

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