Linking Lago as a source

The Lago connector syncs your billing data into PostHog, so you can analyze it alongside your product data. It works with both Lago Cloud and self-hosted Lago instances.

Prerequisites

You need a Lago account with access to create an API key. Self-hosted users also need a publicly reachable Lago host.

Adding a data source

1. In PostHog, go to the Sources tab of the data pipeline section.
2. Click + New source and click Link next to this source.
3. Enter your credentials (see Configuration below) and click Next.
4. Select the tables you want to sync, choose a sync method and frequency, then click Import.

Once the syncs are complete, you can start querying this data in PostHog.

When linking Lago, you'll need:

• API key – create an API key in the Lago dashboard under Developers > API keys.
• API URL – self-hosted only. Set it to your own Lago host (for example https://billing.example.com). Leave it blank to use Lago Cloud.

Sync modes

Each table can be synced in one of several modes, depending on what the source supports:

• Webhook (when available) – the source pushes changes to PostHog in real time. Fastest freshness, lowest ongoing cost, and the only mode that reliably captures updates and deletes.
• Incremental – only new or updated rows are synced on each run, using a cursor field (such as an updated_at timestamp). Cheaper than a full refresh, but deletes aren't captured.
• Append only – new rows are appended using a cursor field; existing rows are never updated. Ideal for immutable, append-only tables like event logs.
• Full refresh – the whole table is reloaded on every sync. Use it when a table has no reliable cursor or when you need deletions reflected.

See sync methods for a full explanation of how each mode works and how to choose between them.

Configuration

Supported tables

The tables available from this source are discovered from your account when you connect it, so the exact list depends on your data. Once connected, you can pick which tables to sync from the sources tab.

Troubleshooting

• If you see an invalid key error, generate a new key in the Lago dashboard, then reconnect.
• If your key lacks the required permissions, check the key and try again.
• If the API URL is not allowed, use a publicly reachable host.

If your sync is failing or data looks wrong, see the Data warehouse troubleshooting guide. If that doesn't help, contact support – we're happy to help.