A knitting needle inventory that understands interchangeable systems. Most inventory tools assume items are atomic. Needles aren't: tips, cables, and connectors combine, and only some combinations are legal.
You're in the shop, pattern in hand. One question: do I already have this?
Checks fixed circulars, buildable interchangeable combinations, and DPNs. Anything in use on a project is called out so you know it exists but isn't free.
Try it
This is loaded with sample data so you can see it working. Add your own items, mark things in use, and the availability and build panels update. Everything saves to your browser only; nothing is sent anywhere. Use Export to keep a copy.
What you can build right now
Derived from available tips and cables whose join size matches. Items in use are excluded. Cables are sold by cable length, so the finished needle is cable plus both tips: an 8" cable with 4" tips gives the familiar 16" circular. Adapters let a tip reach a cable one join size away; a connector plus an adapter chains two cables into one longer composite. Those combinations are flagged below.
Where the compatibility rules come from
Modelled on ChiaoGoo's published interchangeable systems guide (June 2019). Two rules from it drive everything. First, TWIST and SPIN parts interchange whenever the join sizes match, so the product line is irrelevant and only [M], [S], [L] matters. Second, the size-to-join mapping is not constant: US 2 is [M] as a 2" Shortie but [S] as a 4" tip. Other brands are user-editable defaults. Verify against your own needles.
Roadmap
What this v1 deliberately leaves out, and where it goes next.
Scan to addnext
Barcode scan at the store to add a cable or configuration on the spot, without waiting to get home. Uses the phone camera through the browser; matches against a product database, falls back to manual entry.
Cross-device syncnext
Optional login so the list follows you from laptop to phone. Offline stays the source of truth; sync reconciles when there's signal. Last-write-wins is enough for one person's own devices.
Crochet hookslater
Track hooks alongside needles, with quantity so duplicates are visible at a glance. Same "do I already own this?" question, different tool.
Tunisian hookslater
Tunisian crochet hooks are their own category, and interchangeable Tunisian sets (like ChiaoGoo's T-SPIN) share the combinatorial problem this app already models: hook plus cable, by join size.
Why this order
Scan-to-add and sync both serve the same moment the store lookup was built for: capturing and referencing your collection away from home. Crochet and Tunisian hooks broaden the tool from needles to fiber tools generally, which is a larger bet worth making only after the core loop earns its keep.
Add a ChiaoGoo set
Adds every tip in the set at the documented sizes and tip lengths, with the connector class filled in from the size band.