# Tsumobi

**Canonical:** https://apis.io/providers/tsumobi/  
**Website:** http://tsumobi.com  
**APIs profiled:** 0

Tsumobi was a Y Combinator (Winter 2007) mobile messaging startup founded in Boston by Joshua Wilson and Adam Bouhenguel, and later backed by Andreessen Horowitz (a16z). It built a programming language that sat on top of J2ME so feature-phone applications could be downloaded and updated on the fly via URLs, aiming to fix the painful install and upgrade cycle of late-2000s mobile apps. The company is inactive (YC lists it as Inactive; reporting describes the startup as shut down after raising roughly $2M), the tsumobi.com domain no longer serves a website, and no public API, developer portal, SDKs, or specifications were found. This profile is retained as a historical a16z portfolio record in the API Evangelist network.

## Kin Score — 6.4 / 100 (minimal)

Scored 2026-08-21 under rubric 0.12.0. Trend: flat (+0.0 from 6.4).

| Facet | Score |
|---|---|
| Discoverability | 57.4 |
| Contract Quality | 0.0 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 5.3 |
| Developer Ergonomics | 0.0 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

## Agent readiness — 0.0 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| 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 (1)

- **Tsumobi Domain Security** — no transport/DNS hardening detected

## Tags

Company, Messaging, Mobile, J2ME, Feature Phones, Y Combinator, Defunct

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