> AI agents: this is one page from PostHog's docs. Full index of Markdown docs for LLMs: https://posthog.com/llms.txt

# Linking CAST AI as a source

Canonical URL: https://posthog.com/docs/data-pipelines/sources/cast-ai

> **Cloud region:** This page uses US Cloud hosts. For an EU Cloud project, use `https://eu.posthog.com` instead of `https://us.posthog.com` or `https://app.posthog.com` (app host for links).

## On this page

- [Prerequisites](#prerequisites)
- [Adding a data source](#adding-a-data-source)
- [Sync modes](#sync-modes)
- [Configuration](#configuration)
- [Supported tables](#supported-tables)
- [Troubleshooting](#troubleshooting)

**Beta release**

This source is currently in **beta**. It works end to end, but you may still hit rough edges. [Let us know](https://us.posthog.com/#panel=support%3Asupport%3Adata_warehouse%3A%3Atrue) if you do.

![](https://res.cloudinary.com/dmukukwp6/image/upload/texture_tan_9608fcca70)

![](https://res.cloudinary.com/dmukukwp6/image/upload/texture_tan_dark_a92b0e022d)

Let AI connect your sources for you

Skip the manual setup — run this in your project and the wizard auto-detects your databases and APIs and connects them to PostHog.

`npx @posthog/wizard warehouse`

![PostHog Wizard hedgehog](https://res.cloudinary.com/dmukukwp6/image/upload/wizard_3f8bb7a240.png)

![](https://res.cloudinary.com/dmukukwp6/image/upload/wizard_3f8bb7a240.png)Let AI connect your sources for you

The CAST AI connector syncs your Kubernetes cost and savings data from [CAST AI](https://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](https://app.posthog.com/data-management/sources) of the data pipeline section.
2.  Click **\+ New source** and click **Link** next to this source.
3.  Enter your credentials (see [Configuration](#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](https://docs.cast.ai/docs/api-access) 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](https://posthog.com/docs/data-pipelines/sources.md#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

| Option | Type | Required |
| --- | --- | --- |
| `API key` | password | Yes |

## Supported tables

| Table | Description | Sync method | Incremental field | Primary key |
| --- | --- | --- | --- | --- |
| `clusters` | A Kubernetes cluster connected to CAST AI for cost monitoring and optimization. | Full refresh | — | — |
| `cluster_cost_reports` | Historical compute cost for a cluster, bucketed by time interval and broken down by on-demand, spot, and spot-fallback instance cost. | Incremental, Full refresh | timestamp | — |
| `cluster_savings_history` | Historical comparison of a cluster's real cost against CAST AI's estimated optimal cost under different optimization strategies, used to track realized and available savings. | Incremental, Full refresh | createdAt | — |
| `cluster_savings_reports` | Realized savings for a cluster, bucketed by time interval and split into savings from downscaling and savings from spot instances. | Incremental, Full refresh | timestamp | — |
| `workload_cost_reports` | Compute cost of each workload in a cluster over the sync's report window, with daily cost metrics, workload labels, and a cost summary. | Full refresh | — | — |
| `workload_efficiency_reports` | Requested, used, and wasted CPU and memory of each workload in a cluster over the sync's report window, with the cost impact of the waste. | Full refresh | — | — |
| `workload_data_transfer_costs` | Network data transfer bytes and cost of each workload in a cluster over the sync's report window, split by traffic type (internet, inter-region, inter-zone, intra-zone, cloud API). | Full refresh | — | — |

## 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](https://posthog.com/docs/data-warehouse/troubleshooting.md). If that doesn't help, [contact support](https://us.posthog.com/#panel=support%3Asupport%3Adata_warehouse%3A%3Atrue) – we're happy to help.