# Lakefront

> An HTAP engine on DuckLake: durable writes in Postgres, per-board DuckDB replicas for serving, one npm package.

## Docs

- [Lakefront](https://lakefront.folsomintelligence.com/): An HTAP engine on DuckLake for point writes and analytical queries, without a separate ETL pipeline.

## Start

- [Quickstart](https://lakefront.folsomintelligence.com/guides/quickstart): Install Lakefront, start the catalog Postgres, and write and read your first board.
- [Fundamentals](https://lakefront.folsomintelligence.com/guides/fundamentals): Boards, watermarks, write paths, replicas, watch, and the conventions every page assumes.
- [Tutorial](https://lakefront.folsomintelligence.com/guides/tutorial): One continuous scenario across schema evolution, a declared board, transactions, watch, and the HTTP client.

## Data

- [Write data](https://lakefront.folsomintelligence.com/guides/writes): Insert, patch, delete, and append-upsert rows on a board, from the embedded engine or the HTTP client.
- [Query](https://lakefront.folsomintelligence.com/guides/queries): Run SQL against a board's replica from the engine, or build it with Kysely through the HTTP client.
- [Boards and schema](https://lakefront.folsomintelligence.com/guides/schema): How a board's schema comes to be, inferred from data or declared up front, plus column widening and the explicit lifecycle calls.
- [Transactions](https://lakefront.folsomintelligence.com/guides/transactions): Run atomic multi-board writes with engine.transaction, and why the HTTP client can't.
- [Idempotent writes and retries](https://lakefront.folsomintelligence.com/guides/idempotency): Make a mutation safely retryable with idempotencyKey, and what happens when you don't.
- [Watch](https://lakefront.folsomintelligence.com/guides/watch): Follow a board's writes as they land, with the design behind catch-up, retention, and resync.

## Deploy

- [Serve over HTTP](https://lakefront.folsomintelligence.com/guides/http): Start a server node with serve, then talk to it with the typed client or the raw RPC client.
- [Turn on auth](https://lakefront.folsomintelligence.com/guides/auth): How a capability token authorizes a request, how to mint and narrow one, and how to manage the keys that sign them.
- [Run a cluster](https://lakefront.folsomintelligence.com/guides/cluster): How to deploy a Lakefront cluster, N server nodes and a router sharing one catalog Postgres and one object store, plus a local compose demo of the same topology.
- [Operations](https://lakefront.folsomintelligence.com/guides/operations): The flusher, manual flush and maintenance, parked boards, engine stats, eviction, and the destructive operations that stay off the Engine surface.

## Tools

- [Benchmarking](https://lakefront.folsomintelligence.com/guides/benchmark): Run the OLTP, engine, and ClickBench suites, and how to read what each one reports.
- [Troubleshooting](https://lakefront.folsomintelligence.com/guides/troubleshooting): Symptom-first fixes for the failures that actually come up running lakefront.

## Concepts

- [Architecture](https://lakefront.folsomintelligence.com/concepts): How Lakefront splits writes and reads across a WAL-backed truth store and per-board replicas, and where that shape wins or loses.
- [Truth store](https://lakefront.folsomintelligence.com/concepts/truth-store): Why DuckLake serves as Lakefront's source of truth instead of a plain database, and what that costs in inlining, snapshot retention, and per-lake namespacing.
- [Replicas and serving](https://lakefront.folsomintelligence.com/concepts/replicas): What makes a replica disposable rather than authoritative. Sync-then-query freshness, cache outcomes, eviction under load, and ART indexing for point lookups.
- [Write paths](https://lakefront.folsomintelligence.com/concepts/write-paths): The durability contract behind writePath "wal" and "lake". Group commit, WAL ordering, the flusher, and what survives a crash.
- [Consistency and watermarks](https://lakefront.folsomintelligence.com/concepts/consistency): The watermark model behind Lakefront's reads and writes. Bounded staleness by default, read-your-write on request, and what neither buys you.
- [Routing](https://lakefront.folsomintelligence.com/concepts/routing): Weighted rendezvous hashing for node selection, hedged reads, and why writes get exactly one attempt unless they opt in.
- [Capability tokens](https://lakefront.folsomintelligence.com/concepts/tokens): Lakefront's auth model. Macaroon-style tokens that any holder can attenuate offline, with no server-side revocation list.
- [Performance](https://lakefront.folsomintelligence.com/concepts/performance): Transactional throughput and latency against Postgres, analytical results on ClickBench, and the machine and methodology behind every number.

## Reference

- [Overview](https://lakefront.folsomintelligence.com/reference): Every Lakefront export, option, and wire shape, by import path.
- [Engine](https://lakefront.folsomintelligence.com/reference/engine): open/openSafe and the Engine class, covering reads, writes, transactions, declared boards, watch, and operational helpers.
- [Client](https://lakefront.folsomintelligence.com/reference/client): connect and BoardClient, covering raw SQL queries, the board-rooted builder, mutation methods, and watch for lakefront/client.
- [Server](https://lakefront.folsomintelligence.com/reference/server): serve, the HTTP front end that puts a server node's routes, auth, and SSE stream in front of an Engine.
- [Router](https://lakefront.folsomintelligence.com/reference/router): route and the Router/Membership/hashing internals behind cache-affinity routing, hedging, and failover.
- [Contract](https://lakefront.folsomintelligence.com/reference/contract): The wire contract, covering every procedure's shapes, the RPC transport client, capability tokens, and the tagged error catalog.
- [Wire protocol](https://lakefront.folsomintelligence.com/reference/wire-protocol): The HTTP envelope, headers, status codes, and SSE event format every Lakefront client and router speaks.
- [Environment variables](https://lakefront.folsomintelligence.com/reference/environment): Every environment variable read by the server node's and router's standalone (container) entrypoints.
- [Errors](https://lakefront.folsomintelligence.com/reference/errors): The full tagged-error catalog, covering engine errors, wire-only tags, and how each failure surfaces to a caller.

## Other

- [v0.1.0](https://lakefront.folsomintelligence.com/changelog/v0-1-0)

## RSS Feeds

- [Lakefront — Changelog](https://lakefront.folsomintelligence.com/changelog/rss.xml)