Seeed Studio XIAO (all variants) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/seeed-xiao/  (CC BY 4.0)
Basis: published spec and STEP
Catalog version: 2026-10-20

Overall (mm): length 21, width 17.5
- Thumb-sized; USB-C on one short edge; 7 castellated pads per long edge on 2.54 mm pitch.
- All XIAO variants share the outline, so one enclosure fits every chip.

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Seeed Studio (official): XIAO ESP32C3 wiki (dimensions, STEP download) — STEP, PDF — see page [verify license at link] — https://wiki.seeedstudio.com/XIAO_ESP32C3_Getting_Started/

Xem Studio scan: not planned; the official CAD above covers it.
API: https://xemstudio.com/api/geometry?object=seeed-xiao