latlng — Open-source geospatial object engine in Rust + WebAssembly

R-tree spatial indexing and field indexes for nearby, within, intersects, scan, and text search — backed by a portable Rust core.

Define hooks with circles, bounds, GeoJSON areas, or roaming distance. Emit inside, outside, enter, exit, cross, and roam events as objects move.

Durable HTTP POST delivery from a SQLite-backed outbox. Per-request timeouts, exponential backoff, dead-letter — at-least-once with stable event IDs.

HTTP/JSON with generated OpenAPI, WebSocket subscriptions, and async Cap'n Proto RPC — all backed by the same engine and auth model.

Run the server in memory or on an append-only file. The Rust storage layer also includes SQLite for embedded use, plus AOF compaction, verification, backup, and restore.

Streaming replication over Cap'n Proto with checksum-based resume. Read-only followers catch up incrementally and serve queries after initial sync.

Static bearer tokens, HMAC JWTs, asymmetric JWTs from PEM keys or JWKS. Claims-based authz scoped per collection.

The same engine compiles to wasm and runs in a Web Worker. Build local-first map apps with no server in the loop — like the demo above.

Prometheus metrics, structured logging, HTTP rate limits per principal, runtime config rewrite — built for production, not just demos.

Native server

latlng-server

Run it as a standalone process. HTTP/JSON, WebSocket subscriptions, and async Cap'n Proto RPC, all from the same binary, behind the same auth.

# Start the server binary
latlng-server

# Store a point
curl -sS -X POST http://127.0.0.1:7421/collections/fleet/objects/truck-1 \
  -H 'content-type: application/json' \
  -d '{"object":{"Point":{"lat":53.55,"lon":9.99,"z":null}}}'

# Query nearby points
curl -sS -X POST http://127.0.0.1:7421/collections/fleet/search/nearby \
  -H 'content-type: application/json' \
  -d '{"lat":53.55,"lon":9.99,"meters":1000,"options":{}}'

Browser

@latlng/wasm

The same engine, compiled to WebAssembly and pinned inside a Web Worker. Local-first geospatial — no server, no network, no key.

import { createLatLng } from "@latlng/wasm";

const db = await createLatLng();
await db.createCollection("fleet");
await db.setPoint("fleet", "truck-1", { lat: 53.55, lon: 9.99 });

const nearby = await db.nearby("fleet", {
  lat: 53.55,
  lon: 9.99,
  meters: 1000,
});

console.log(nearby.results);