# Duolingo

**Canonical:** https://apis.io/providers/duolingo/  
**Website:** https://www.duolingo.com  
**APIs profiled:** 0

Duolingo (NASDAQ: DUOL) is a Pittsburgh, Pennsylvania based learning technology company best known for the Duolingo language-learning app, the world's most-downloaded education app, offering courses in more than 40 languages including Spanish, English, French, German, Italian, Portuguese, Japanese, and Chinese. Founded in 2011 by Luis von Ahn and Severin Hacker, Duolingo has expanded its consumer learning footprint beyond languages with Duolingo Math, Duolingo Music, a newly rolled-out Chess course, and Duolingo ABC for early literacy, all delivered through the same gamified, streak- driven mobile experience. The Company also operates the Duolingo English Test, a digital English-proficiency exam accepted by thousands of higher- education institutions, certification programs, and government agencies worldwide as an alternative to TOEFL and IELTS. Duolingo monetizes through Super Duolingo and Duolingo Max subscriptions, in-app advertising, in-app purchases, and Duolingo English Test fees. The company surpassed 50 million daily active users in Q3 2025 and reported 41% revenue growth in Q2 2025. Duolingo does not publish an official public developer API, SDK, or developer portal; integrations with the Duolingo English Test (score-send to institutional CRMs such as Slate) are handled through a private API-key program negotiated directly with accepting institutions. Community- maintained reverse-engineered clients exist against the unofficial https://www.duolingo.com/api/1 surface but are not endorsed by Duolingo.

## Kin Score — 15.1 / 100 (emerging)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 15.1).

| Facet | Score |
|---|---|
| Discoverability | 50.0 |
| Contract Quality | 38.9 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 5.3 |
| Developer Ergonomics | 2.4 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

Regulatory layer — **Education & Research**: 22.2 (matched via tags).

## Agent readiness — 15.4 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## Security (2)

- **Duolingo Domain Security** — TLSv1.3 · DMARC
- **Duolingo Vulnerability Disclosure** — security.txt · contact published

## Tags

Language Learning, Education, EdTech, Mobile Learning, Gamification, Language Assessment, English Proficiency, Math Learning, Music Learning, Early Literacy, Consumer Apps, Subscription

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/duolingo/). Scores are computed from the provider's own public artifacts under a published rubric.