Syncing custom taxonomies

How to sync WordPress custom taxonomies with Whalesync

Whalesync automatically discovers the two built-in WordPress taxonomies — Categories and Tags — and surfaces them as their own tables you can map (see Supporting tables).

How to sync to a custom taxonomy

WordPress represents a taxonomy assignment on a post as the taxonomy term's numeric ID, not its name. So to sync a custom taxonomy, you map a field containing the term ID(s) to one of these columns on your Posts, Pages, or custom post type table:

  • The native taxonomy field WordPress adds to the post type when the taxonomy is registered with Show in REST API enabled and associated with that post type.

  • An ACF field of type "Taxonomy", if you've set one up.

Both accept the numeric term ID and check off the matching term on the post.

1. Find the term IDs

You can find a term's ID either way:

  • List the taxonomy's terms at https://your-site.com/wp-json/wp/v2/<taxonomy> and read each term's id.

  • Or open the term's edit page in WordPress admin — the ID is the tag_ID value in the URL (e.g. .../term.php?taxonomy=site-category&tag_ID=22).

2. Get the IDs into your source

Because WordPress wants the ID and not the label, the cleanest setup in Airtable is a small lookup table:

  1. Create a table that maps each term's name to its WordPress ID.

  2. On the table you're syncing, add a "Link to another record" field pointing at that lookup table, plus a Lookup field that pulls in the ID.

  3. Sync the Lookup field. This way you pick terms by name in Airtable instead of memorizing IDs.

3. Map it in Whalesync

Map that ID field to the taxonomy column on the matching post type table, and run your sync. The term will be assigned to the post the same way the built-in Categories field works.

Tip: To assign more than one term to a record, use a field that outputs multiple IDs and toggle "allow linking to multiple records" so multiple values sync through.

Notes

  • Terms must already exist in WordPress. This assigns posts to existing terms by their ID — it does not create new terms in the taxonomy. Create the terms in WordPress first, and keep your lookup table up to date if you add more.

  • Permissions: make sure the WordPress user Whalesync connects with is an Editor or Admin so it is allowed to assign terms.

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