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

# Linking crates.io as a source

Canonical URL: https://posthog.com/docs/data-pipelines/sources/crates-io

> **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)

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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 crates.io connector syncs crates, versions, downloads, and more into the PostHog data warehouse, so you can analyze them alongside your product data.

## Prerequisites

None. The crates.io API is public, so no account or API key is needed.

## 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.

Pull metadata, versions, owners, and daily download counts for Rust crates from the [crates.io](https://crates.io) API.

crates.io's read APIs are public, so no credentials are required. There is no practical way to sync the whole registry, so enter the crate names you want to track, one per line (or comma-separated). For example:

```
serde
tokio
posthog-rs
```

Each sync fetches the current data for every configured crate. crates.io has no server-side "changed since" filter, and daily download counts only cover the trailing ~90 days, so all tables sync as a full refresh.

You'll be asked for:

-   **Crates**: for example `serde tokio posthog-rs`.

## 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.

All crates.io tables are full refresh. Each sync replaces the contents of the table.

## Configuration

| Option | Type | Required |
| --- | --- | --- |
| `Crates` | textarea | Yes |

## Supported tables

| Table | Description | Sync method | Incremental field | Primary key |
| --- | --- | --- | --- | --- |
| `crates` | Crate metadata: one row per configured crate, from the `crate` block of the crates.io API crate detail endpoint. | Full refresh | — | — |
| `versions` | Published versions: one row per version across every configured crate. | Full refresh | created\_at | — |
| `downloads` | Daily download counts per version of each configured crate, over the trailing ~90-day window the crates.io API exposes. | Full refresh | date | — |
| `version_downloads` | Daily download counts for each of the most recent versions of each configured crate, over the trailing ~90-day window the crates.io API exposes. | Full refresh | date | — |
| `owners` | Owners (users and teams) of each configured crate. | Full refresh | — | — |
| `dependencies` | Dependencies declared by the most recent versions of each configured crate, one row per dependency edge. | Full refresh | — | — |
| `reverse_dependencies` | Versions of other crates that depend on each configured crate, one row per dependency edge. | Full refresh | — | — |
| `categories` | Every category on crates.io, resolving the category slugs carried on crate records, with the number of crates in each. | Full refresh | — | — |
| `keywords` | Every keyword on crates.io, resolving the keywords carried on crate records, with the number of crates using each. | Full refresh | — | — |

## Troubleshooting

-   If the connection fails with an authorization error, the API key is wrong, expired, or has been revoked. Create a new one, then reconnect the source.
-   If a table syncs no rows, the credential may not have access to that data. Check its permissions, then reconnect the source.

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.