BlockChalk
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.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles BlockChalk the way a machine reads it — 3 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — BlockChalk scores 25.3/100 (emerging), with a separate agent-readiness read of 21/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile BlockChalk
Each block below is one kind of artifact we hold for BlockChalk. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 1
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
BlockChalk chalks API
Location-pinned neighborhood messages.
Security Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Resources
Every other property we hold for BlockChalk — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 2
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 1
Authentication, authorization, and security posture
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