Laredo

Real-time data sync from databases to in-memory targets. Laredo captures a consistent baseline snapshot of configured tables, then streams all subsequent changes (inserts, updates, deletes, truncates) through pluggable targets. It supports indexed in-memory replicas, HTTP forwarding, replication fan-out, snapshots, and a full gRPC management API.

What Laredo does

Laredo sits between your database and your application's in-memory state. It handles all the complexity of logical replication, change streaming, ACK coordination, and snapshot management, and exposes clean Go interfaces that any application can use.

  PostgreSQL (logical replication)
       |
  ┌────▼─────┐
  │  Laredo   │
  │  Engine   │
  └──┬──┬──┬──┘
     │  │  │
     ▼  ▼  ▼
  Indexed   HTTP    Replication
  Memory    Sync    Fan-Out
  Target    Target  Target
                      |
               ┌──────┼──────┐
               ▼      ▼      ▼
            Client  Client  Client

Key features

• Consistent baselines — point-in-time snapshots via PostgreSQL's exported snapshot mechanism, with no gaps between baseline and stream
• Pluggable targets — indexed in-memory store, compiled domain objects, HTTP sync, or replication fan-out
• Pipeline model — per-table filter and transform chains between source and target
• ACK coordination — source positions advance only after all targets confirm durability
• Snapshot system — periodic serialization of target state for fast restart without full re-baseline
• Error isolation — one pipeline can fail without affecting others
• Replication fan-out — multiplex one PostgreSQL slot to N gRPC clients with snapshot + journal + live stream
• gRPC management — OAM service for status, reload, pause/resume, snapshot management
• Query API — gRPC service for looking up rows in in-memory targets
• CLI tool — laredo command for inspecting and managing a running server
• Zero-opinion core — the library has no config format, transport, or logging dependencies

Three layers

Layer	Description	When to use
Core Library	Engine, interfaces, types, pipeline orchestration	Embedding in your Go application
Optional Modules	gRPC services, HOCON config, metrics, source/target implementations	Adding management or specific data sources
Pre-built Service	laredo-server binary with config, gRPC, metrics, signal handling	Running as a standalone service

Next steps

• Quick Start to get running in under 5 minutes
• Architecture to understand the design
• PostgreSQL Source for configuring logical replication
• CLI Reference for the laredo command