Linking CAST AI as a source

The CAST AI connector syncs your Kubernetes cost and savings data from CAST AI into the PostHog data warehouse. This lets you analyze cluster costs, spot vs on-demand spend, and optimization savings alongside your product analytics.

Prerequisites

You need a CAST AI account with API access enabled. A read-only API key is sufficient.

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 CAST AI, you'll need:

• API key – create one in your CAST AI console under API Access settings.

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.

The clusters table always syncs as full refresh since the CAST AI API has no server-side timestamp filter for it.

The cluster_cost_reports and cluster_savings_history tables support incremental syncs on their timestamp fields, which we recommend to avoid re-fetching historical data on every sync.

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

• Authentication error (401): your API key is invalid or has been revoked. Create a new key in your CAST AI console under API Access settings, then reconnect.
• Permissions error (403): your API key does not have the required permissions. Check the key's scopes in your CAST AI console, then reconnect.

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.