How Sizes Work Across Channels

FLUF auto-resolves sizes when crosslisting. You don't need to set up size mappings manually for any channel — the system understands common formats (e.g. UK 12, EU 38, IT 48, M, Size 10, Shoe Size 10 (UK)) and converts them at export time.

What "auto-resolves" means

When you crosslist a product, FLUF reads the size you set on the FLUF product (the Size attribute) and converts it into whatever the destination marketplace expects:

• Vestiaire Collective — picks size_unit (US, EU, UK, IT, KR, International) and size_id based on the prefix you provide and the listing category.
• Vinted — looks up the matching size_id in Vinted's per-catalog size table.
• eBay — passes through as item specifics; you'll see the value you typed on the eBay listing.
• Depop / Shopify / Etsy / Yaga — pass through with light normalisation.
• Wallapop — matched to the size options Wallapop offers for the chosen category (it shows letter, EU and UK equivalents, e.g. M / 38 / 10).

You write the size once on the FLUF product; the channel-specific format is figured out for you.

Recommended formats to enter

For best results when your size is regional, use a prefix:

Vestiaire Collective — important detail about regional sizing

Not every category on Vestiaire supports every size unit. For example, most Women's clothing categories accept US and International sizing — but not IT. Men's tailoring categories do accept IT.

When you enter a regional size that the chosen category doesn't support (e.g. IT 48 on a Women's coat), FLUF falls back through US → EU → UK → International and picks the closest match. The listing still goes through, but on Vestiaire's side it will appear under whichever unit the category actually supports — not necessarily the one you typed.

If the size on Vestiaire isn't what you expected:

• Try the same numeric size with a different prefix (EU 48, US 48).
• Or enter just the number with no prefix.
• Or change the listing category if you specifically need IT sizing.

When the size shown in your draft doesn't match what hits the channel

The Draft Review screen shows the raw text you typed. The actual unit/ID sent to the marketplace is computed at dispatch time. So a draft that says IT 48 may end up on Vestiaire as US 48 (or whichever unit the category supports). This is expected — not a bug.

What you do NOT need to do

• You do not need to create a size mapping override. Size is handled automatically — there's no per-user size mapping system to set up.
• You do not need to convert sizes manually before listing. Enter the size in your usual regional format and FLUF handles the conversion.
• You do not need to match a specific list of "accepted sizes" for each channel. The categories on the channel determine which size units are valid; FLUF picks the right one.

Troubleshooting

"My size shows blank on the channel after crosslisting." The category may not support the size unit you entered, and the fallback also failed. Try a more standard format (M, EU 38, or just the number).

"Vestiaire shows US 48 but I entered IT 48." The category you listed in doesn't support IT sizing, so FLUF fell back to US. This is expected. List in a different category if IT must be preserved.

"My letter sizes (M, L, XL) aren't showing on Vinted." Vinted size availability depends on the catalog. Some categories use letter sizes, others use numeric. FLUF picks from what the catalog allows — if nothing fits, the size will be missing on the listing and you'll see a listing error.

If you've tried the above and the size still doesn't come through correctly, contact support at [email protected] or WhatsApp +27 79 362 4993 with your product ID.