WordsAPI

What WordsAPI does

WordsAPI is a privately held, bootstrapped company founded in 2015 and based in Virginia, USA, that operates a RESTful API providing structured English language lexical data for approximately 325,000 words. The product exposes definitions, synonyms, antonyms, examples, pronunciation (IPA), syllable counts, rhymes, usage frequency metrics, and an unusually rich set of hierarchical semantic relationships (typeOf, partOf, substanceOf, memberOf, inCategory, entails, and similar) sourced from Princeton's WordNet, the CMU Pronouncing Dictionary, and the Open Subtitles corpus.

The company's core technical asset is the curated assembly and packaging of these open-source linguistic databases into a single JSON API, supported by SDKs for Ruby, Python, JavaScript, and PHP. Distribution and billing are handled entirely through the RapidAPI marketplace, and access is also available via a one-time $629 purchase of the full JSON dataset for local hosting. Pricing is structured as a freemium tier (2,500 requests/day) plus three paid subscription tiers ($10, $49, and $89 per month for 25K, 250K, and 500K daily requests respectively).

WordsAPI targets a horizontal, developer-led customer base including word game and crossword builders, educational technology and language learning applications, and NLP/AI developers needing lexical retrieval. The company has no disclosed external funding, no named management team, and limited recent public activity, with the most recent blog post dating to June 2019 and the website copyright ending in 2019, suggesting an operationally stable but minimally evolving business.

Name

WordsAPI

Legal name

WordsAPI

Website

https://wordsapi.com

Company type

Private

Founded year

2015

Operating status

Operating

Short description

WordsAPI is a bootstrapped Virginia-based company providing a RESTful API for English lexical data — including definitions, synonyms, pronunciation, hierarchical word relationships, and frequency metrics for 325,000+ words — sold via subscription tiers and a one-time data license through the RapidAPI marketplace to game developers, edtech builders, and NLP applications.

Ownership category

akta.pro rank

Product category

Language Data API

NAICS

Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services (518)

SIC

Services-Computer Programming, Data Processing, Etc. (7370)

akta.pro primary industry

Knowledge Graphs, Ontologies & Entity Resolution (HDAAADAI)

akta.pro secondary industry

NLP Developer Tools & Evaluation (prompting, testing, benchmarks) (HDAAADAK)

Keywords

• Dictionary API
• English lexical data
• Thesaurus API
• Linguistic database API
• Word relationship API

Headquarters

HQ city

Virginia

HQ country

United States

HQ region

North America

Markets served

GTM type

B2B

Offering type

Software

Cost components

Technology or R&D, Infrastructure, Operations, Personnel, Marketing or Sales

Revenue model

1. API Subscription Plans: Monthly subscription plans with tiered API request limits, billed through RapidAPI platform
2. Data License Purchase: One-time purchase of complete WordsAPI dataset for local hosting and unlimited use, excluding resale rights and competitive services

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels4 records

Core offering

WordsAPI provides a RESTful API delivering comprehensive English language lexical data for 325,000+ words, including definitions, synonyms, antonyms, examples, rhymes, IPA pronunciation, syllable counts, word usage frequency metrics, and an extensive set of hierarchical semantic relationships (typeOf, partOf, substanceOf, memberOf, etc.). The data is aggregated from authoritative open lexical sources (WordNet, CMU Pronouncing Dictionary, Open Subtitles corpus) and is consumed programmatically by developers integrating word intelligence into games, educational platforms, and NLP applications. Access and billing are managed through the RapidAPI marketplace, with an optional one-time download of the full JSON dataset for local hosting.

Product overview

WordsAPI is a single unified API product providing comprehensive English language lexical data. The core WordsAPI service delivers definitions, synonyms, antonyms, rhyming words, frequency statistics, pronunciation information, syllable breakdowns, and hierarchical word relationships through a RESTful API. An accompanying data product offers a downloadable JSON data set of over 325,000 words for local hosting at a one-time purchase price. Both products share the same underlying lexical database derived from WordNet, Open Subtitles, and the CMU Pronouncing Dictionary.

Differentiator

Problem solved

Functional benefit

Products and services

• WordsAPI A RESTful API providing comprehensive English language data including definitions, synonyms, antonyms, examples, rhymes, frequency information, pronunciation (IPA), syllable counts, and hierarchical word relationships for over 325,000 words. Data is sourced from WordNet, Open Subtitles, and the CMU Pronouncing Dictionary. Sold via tiered subscriptions on the RapidAPI marketplace; intended for developers integrating word intelligence into games, educational platforms, and NLP applications.
• Words API Data Set A downloadable JSON dataset of the entire WordsAPI database (over 325,000 words) available for a one-time $629 purchase. Buyers receive unlimited usage rights for local hosting, with restrictions on resale and competitive use. Intended for developers and teams that want to run the data on their own infrastructure.

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

AI capability2 records

Feature5 records

Partnerships

Four partnerships are on record, tiered core.

• RapidAPIcoreChannel Partner/ Reseller/ DistributorRapidAPI handles all account billing and API access for WordsAPI subscription plans. Users sign up and manage their API keys through the RapidAPI platform.
• WordNet (Princeton University)coreTechnology or IntegrationWord definitions and word relationships (typeOf, hasTypes, partOf, hasParts, etc.) are derived from the WordNet lexical database maintained by Princeton University.
• CMU Pronouncing DictionarycoreTechnology or IntegrationPronunciation and syllable information sourced from The CMU Pronouncing Dictionary for IPA pronunciation data.
• Open SubtitlescoreTechnology or IntegrationWord frequency data calculated using corpus data from Open Subtitles, processed using open-source tools available on GitHub.

Scale indicators6 records

Recent moves6 records

Expansion highlights4 records

Emerging players

• NLTK (Natural Language Toolkit): NLTK is a leading open-source Python library providing lexical resources including WordNet access offline. While not a hosted API, it offers similar functionality for developers who can run their own infrastructure, undermining WordsAPI's value proposition.

Direct peers

• DictionaryAPI.dev (Free Dictionary API): A free, open-source REST dictionary API providing definitions, phonetics, and meanings. Directly competes on developer-friendly lexical data access, though without WordsAPI's hierarchical relationships and frequency data.
• Wordnik: Wordnik offers a developer API for English lexical data including definitions, examples, and word relationships sourced from multiple dictionaries. Historically a direct competitor to WordsAPI in the dictionary API space.
• Datamuse: Datamuse provides a word-finding API with similar functionality (definitions, synonyms, related words, contextual scoring) targeted at developers building word games and writing tools - directly competes with WordsAPI in the same developer API category.

Others

• RapidAPI Marketplace: RapidAPI is WordsAPI's primary distribution platform - a marketplace hosting thousands of APIs where developers discover, subscribe to, and bill for WordsAPI access. Also enables competitor APIs (Datamuse, etc.) on the same marketplace.
• Wiktionary (Wikimedia): Wiktionary is the free, open-source lexical data source that WordsAPI's data could be replicated from. While not a paid product, it represents the open data alternative that defines the floor pricing for lexical APIs.

Broad incumbents

• Merriam-Webster Developer Center: Merriam-Webster provides official dictionary APIs (Collegiate, Learner's, Medical, etc.) with definitions, pronunciations, and synonyms. A much larger incumbent publisher offering authoritative, well-funded lexical data services.
• Oxford Dictionaries API: Oxford University Press offers a premium dictionary API with definitions, translations, and lexical data from authoritative Oxford dictionaries. Competes at a higher price/quality tier than WordsAPI.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat3 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/WordsAPI
• GitHubgithub.com/WordsAPI

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about WordsAPI