---
title: Environment variables
description: Every environment variable read by the server node's and router's standalone (container) entrypoints.
---

Embedded use, calling `open` or `serve`/`route` from code, takes options directly and reads no env at all. Everything below maps to a field on `OpenOptions`, `ServeOptions`, or `RouteOptions`, as read by `serving/main.ts` and `router/main.ts` respectively.

## Server node

Read by `serving/main.ts`, via the helpers in `serving/config.ts`.

| Variable                       | Type                     | Default                                      | Maps to                                                                                                                                  |
| ------------------------------ | ------------------------ | -------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
| `LAKEFRONT_POSTGRES`           | string (URL or DSN)      | — required, throws if unset                  | `OpenOptions.postgres`: accepts a standard `postgres://user:pass@host/db` URL or the keyword/value form.                                 |
| `LAKEFRONT_DATA`               | string                   | — required, throws if unset                  | `OpenOptions.data`                                                                                                                       |
| `LAKEFRONT_NAMESPACE`          | string                   | `"lakefront"`                                | `OpenOptions.namespace`                                                                                                                  |
| `LAKEFRONT_S3_ENDPOINT`        | string                   | unset (no S3 config)                         | `OpenOptions.s3.endpoint`: setting this makes `LAKEFRONT_S3_KEY_ID` and `LAKEFRONT_S3_SECRET` required                                   |
| `LAKEFRONT_S3_KEY_ID`          | string                   | — required if `LAKEFRONT_S3_ENDPOINT` is set | `OpenOptions.s3.keyId`                                                                                                                   |
| `LAKEFRONT_S3_SECRET`          | string                   | — required if `LAKEFRONT_S3_ENDPOINT` is set | `OpenOptions.s3.secret`                                                                                                                  |
| `LAKEFRONT_S3_SSL`             | `"true"` / anything else | `false`                                      | `OpenOptions.s3.ssl`                                                                                                                     |
| `LAKEFRONT_INLINING_ROW_LIMIT` | integer                  | unset (engine default `10_000` applies)      | `OpenOptions.inliningRowLimit`                                                                                                           |
| `LAKEFRONT_CACHE`              | string (path)            | `"/cache"`                                   | `OpenOptions.cache`                                                                                                                      |
| `LAKEFRONT_CACHE_CAPACITY`     | integer                  | `256`                                        | `OpenOptions.cacheCapacity`                                                                                                              |
| `LAKEFRONT_POOL_SIZE`          | integer                  | `24`                                         | `OpenOptions.poolSize`                                                                                                                   |
| `LAKEFRONT_WRITE_PATH`         | `"wal"` / `"lake"`       | `"wal"`                                      | `OpenOptions.writePath`: unset, `""`, or `"wal"` all resolve to `"wal"`; anything else must be exactly `"lake"` or the entrypoint throws |
| `LAKEFRONT_FLUSH_INTERVAL_MS`  | integer                  | unset (engine default `30_000` applies)      | `OpenOptions.flushIntervalMs`                                                                                                            |
| `LAKEFRONT_INDEX_COLUMNS`      | comma-separated string   | unset (engine default `["id"]` applies)      | `OpenOptions.indexColumns`: always includes `"id"`; the env value adds columns beyond it                                                 |
| `LAKEFRONT_AUTH`               | `"registry"` / `"none"`  | unset (auth off)                             | `ServeOptions.auth = { registry: true }` when `"registry"`; throws if set to anything else besides `"none"`                              |
| `LAKEFRONT_AUTH_SECRET`        | string                   | unset                                        | `ServeOptions.auth = { secret }`: takes priority over `LAKEFRONT_AUTH` when both are set                                                 |
| `LAKEFRONT_NODE_ID`            | string                   | `` `node-${process.pid}` ``                  | `ServeOptions.nodeId`                                                                                                                    |
| `PORT`                         | integer                  | `8080`                                       | `ServeOptions.port`                                                                                                                      |

Write-path semantics (durability, group commit, the flusher) are covered under [write paths](/concepts/write-paths). The full `OpenOptions` knob table, with the trade-offs behind each default, is in the [engine reference](/reference/engine).

## Router

Read by `router/main.ts`.

| Variable             | Type                           | Default                     | Maps to                     |
| -------------------- | ------------------------------ | --------------------------- | --------------------------- |
| `LAKEFRONT_NODES`    | comma-separated `id=url` pairs | — required, throws if empty | `RouteOptions.nodes`        |
| `LAKEFRONT_HEDGE_MS` | integer                        | `250`                       | `RouteOptions.hedgeDelayMs` |
| `PORT`               | integer                        | `8080`                      | `RouteOptions.port`         |

## Demo script

`scripts/demo.ts` reads one variable, as a fallback for its first CLI argument:

| Variable           | Type         | Default                    |
| ------------------ | ------------ | -------------------------- |
| `LAKEFRONT_ROUTER` | string (URL) | `"http://127.0.0.1:58000"` |

## compose.yaml walkthrough

The full docker compose topology (which of these variables each service sets, and why the ports are non-default) is covered in the [cluster guide](/guides/cluster).