# BlockChalk

**Canonical:** https://apis.io/providers/blockchalk/  
**APIs profiled:** 1

BlockChalk was a location-based neighborhood messaging service founded in 2009 by Stephen Hood, the former product lead for Delicious, and Dave Baggeroer of the Stanford Institute of Design. Users with GPS-enabled smartphones left short public messages called "chalks" pinned to a specific geographic point, and read the chalks other people had left on their block, so neighbors could ask, answer, praise, gripe, report potholes and lost pets, announce garage sales and organize locally. The company raised $1M in seed financing in May 2010 from Joshua Schachter, Battery Ventures, Founder Collective, Harrison Metal, Mitch Kapor, Josh Stylman, Tom McInerney and David Liu. BlockChalk published a small read-only public API on its developer page, offering XML, JSON and RSS interfaces that returned nearby chalks for a supplied latitude and longitude, later joined by a versioned GeoRSS endpoint. The product and the company are retired: blockchalk.com holds an active domain registration but its delegated nameservers no longer resolve, and no BlockChalk host answers on the public internet. This profile preserves the historical API surface as documentation.

## Kin Score — 16.1 / 100 (emerging)

Scored 2026-08-21 under rubric 0.12.0. Trend: flat (+0.0 from 16.1).

| Facet | Score |
|---|---|
| Discoverability | 75.9 |
| Contract Quality | 12.6 |
| Governance | 16.7 |
| Contract Governance | 16.7 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 16.7 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

## Agent readiness — 21.9 (agent-aware)

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

## Access

Open access — onboarding: open, pricing: unknown, trial: no (confidence: medium).

## APIs (1)

- **BlockChalk chalks API** — Location-pinned neighborhood messages.

## Security (2)

- **Blockchalk Authentication** — 0 schemes
- **Blockchalk Domain Security** — HSTS

## Tags

Company, Location, Geolocation, Social, Messaging, Local, Neighborhood, Mobile, Retired

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