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

# Linking Crossref as a source

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

> **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 Crossref connector syncs works, members, funders, and more into the PostHog data warehouse, so you can analyze them alongside your product data.

## Prerequisites

None. The Crossref 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.

Crossref's API is free and public - no API key needed. Add a contact email to get routed to Crossref's faster "polite pool".

The Works table covers Crossref's full DOI registry (160 million+ records), so set a member ID, funder ID, or journal ISSN below to scope which works sync. The Members, Funders, Types, and Licenses tables always sync in full.

## 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 Crossref tables are full refresh. Each sync replaces the contents of the table.

## Configuration

| Option | Description |
| --- | --- |
| `Contact email (optional)` **Type:** email **Required:** False |  |
| `Crossref member ID (optional)` **Type:** text **Required:** False | Scopes the Works table to one publisher. Look up IDs at [api.crossref.org/members](https://api.crossref.org/members). |
| `Funder ID (optional)` **Type:** text **Required:** False | Scopes the Works table to one funder from the [Open Funder Registry](https://api.crossref.org/funders). |
| `Journal ISSN (optional)` **Type:** text **Required:** False | Scopes the Works table to one journal. |

## Supported tables

| Table | Description | Sync method | Incremental field | Primary key |
| --- | --- | --- | --- | --- |
| `Works` | Scholarly work metadata (DOIs, titles, authors, references) registered with Crossref. | Incremental, Full refresh | Indexed date, Deposited date, Created date | — |
| `Members` | Publisher and society organizations that deposit metadata with Crossref. | Full refresh | — | — |
| `Funders` | Funding bodies in Crossref's Open Funder Registry, used to tag works with grant and funding information. | Full refresh | — | — |
| `Types` | The controlled vocabulary of work types Crossref recognizes (journal-article, book-chapter, dataset, etc). | Full refresh | — | — |
| `Licenses` | Distinct license URLs referenced by works, with a count of works that use each. | Full refresh | — | — |
| `Journals` | Journals in Crossref with their ISSNs, publisher, subjects, DOI counts, and metadata coverage statistics. | 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.