Knowledge base
The feedlab knowledge base
The feedlab knowledge base is a free reference for building and fixing product feeds on Shopify, covering every attribute a feed can carry, the specification of each sales channel, the errors channels return, and the vocabulary of feed work.
Sections
Attributes
16Every field a product feed can carry: what it means, how it must be formatted, which channels require it, and where the value lives in Shopify.
Errors
7Disapprovals and warnings, listed under the exact wording the channel shows you, with the cause and the fix for a Shopify catalogue.
Channels
5One page per destination, with the full attribute table for that channel and the differences that catch Shopify merchants out.
Shopify field mappings
20One Shopify field and the attribute it has to become, with the transformation in between. Almost none of them are a straight copy.
Channel comparisons
10Two channels side by side, with every attribute they treat differently and what has to change to reuse one feed on the other.
Product verticals
8Categories whose requirements go beyond the baseline: apparel, food, electronics and the rest, with where those values live in Shopify.
Feed formats
8CSV, TSV, RSS, Atom, JSONL and Parquet, with the escaping rules that decide whether a feed parses and a valid example of each.
Concepts
4The vocabulary of feed work explained from first principles, for anyone who has just been handed a Merchant Center login.
Free tools
Three single-purpose tools built on this reference. Each one runs entirely in your browser, so nothing you paste into it is uploaded.
- Google product category finder This finder searches the full Google product taxonomy by keyword and returns the numeric category ID to put in google_product_category. Each result also says which vertical requirements that branch of the taxonomy brings with it.
- GTIN, EAN and UPC validator This validator checks whether a barcode is a structurally valid GTIN: the right length for EAN-8, UPC-A, EAN-13 or ITF-14, and a check digit that matches the digits before it. It accepts a whole column pasted from a catalogue at once.
- Product feed validator This validator reads a CSV, TSV or XML product feed and checks it against one channel's requirements: which attributes are missing, which values break a format rule, and which ids are duplicated. It parses the file in your browser.
Why this exists
Feed documentation is scattered. The official specifications are authoritative but written for every platform at once, so they never mention Shopify. Community threads are Shopify-specific but rarely accurate for long. Nothing sits in the middle, which is where almost every real question lives: not what an attribute means in the abstract, but which field in a Shopify store it should come from and what breaks when it does not.
This knowledge base is that middle. Every attribute page names the Shopify source and the transformation it needs. Every error page starts from the exact wording a channel shows you and explains why a Shopify catalogue produces it. Every page links to the others, because feed problems are rarely confined to one field.
How to use it
If a channel has rejected something, start in Errors and search for the wording you were shown. If you are building or auditing a mapping, start in Attributes. If you are launching on a channel for the first time, its page in Channels lists every attribute it accepts with the requirement level for each. If a term is unfamiliar, Concepts explains it from first principles.
For machines
This knowledge base is published in plain text as well as HTML. Everything here is free to read, quote and cite, with attribution to feedlab.
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/llms.txtAn index of every page with its one-line definition. -
/llms-full.txtThe complete knowledge base as a single plain-text document. -
/knowledge/channels.jsonEvery channel's attributes and requirement levels as JSON, built from the same data these pages render. -
.mdAppend.mdto any knowledge base URL for the markdown version of that page.
Frequently asked questions
Is the feedlab knowledge base free to use?
Yes. Every page is free to read with no account, and free to quote and cite with attribution to feedlab. It is also published as plain text at /llms.txt and /llms-full.txt for anyone building tools on top of it.
Is this only useful if I use feedlab?
No. The attribute specifications, channel requirements and error explanations apply to any Shopify product feed regardless of how it is generated. Where feedlab handles something specifically, the page says so and is labelled as such.