How the Closo extension works

A 2-minute tour of what your Closo extension does in the background — and why crosslisting needs one.

Updated June 14, 2026

When you crosslist with Closo, something has to actually click the buttons, fill the forms, and upload the photos on Poshmark, Depop, Mercari, and Vinted. That something is the Closo Chrome extension. It runs in your browser and acts as your hands across every marketplace, in parallel, without you switching tabs.

What the extension does, in plain English

Think of the extension as having four jobs. Each one runs quietly in the background, and you almost never see them happen directly.

1. Keep you logged in
When Poshmark or Depop sets a new login cookie, the extension notices and tells Closo. That way, when Closo wants to list a product 20 minutes from now, your session is still alive. You log in once; the extension tracks the rest.
2. Refresh your connection in the background
On a background tick (roughly every 30 minutes) the extension syncs whatever fresh cookies your browsing produced and refreshes Vinted's token actively. For Poshmark, Mercari, and Depop it opens a brief warm-up window on demand when a queued action needs fresher cookies. You won't see a tab open — it happens quietly in the background.
3. List, edit, and delist items
When you press Crosslist on a product, the extension is what actually fills the form on Poshmark, picks the category on Vinted, and uploads photos to Depop. We do this through your browser because marketplaces don't have public APIs for listing.
4. Watch for status updates
When a listing posts, sells, or fails, the extension catches that signal and sends it to Closo so your dashboard stays accurate. Same for price changes and offers.

When it runs

The extension is active whenever Chrome is open. Most of its work happens in three situations:

First, when you ask Closo to do something — list a product, edit a price, delist an item, share a listing. The extension picks up the job from Closo's queue and runs it through your browser session within a few seconds.

Second, on a background tick (roughly every 30 minutes). The extension syncs whatever fresh cookies your normal browsing produced and actively refreshes Vinted's token to stay ahead of its short expiry. For Poshmark, Mercari, and Depop, it doesn't run a fixed timer — instead it opens a brief warm-up window on demand when a queued action needs fresher cookies.

Third, when Closo's server asks it to. If our server detects that your session looks stale (we tried to use it and got a 401), we ask the extension to re-establish the connection on its next active cycle.

When it doesn't run

The extension is paused or absent in these cases. None of them are errors — they're just facts of how Chrome works.

You disabled it in Chrome
Open chrome://extensions and confirm Closo is toggled on. If you removed it accidentally, reinstall from the Chrome Web Store and re-link your marketplaces.
You're using Incognito mode
Extensions don't run in Incognito by default. You can allow Closo specifically — Chrome's extension settings has an 'Allow in Incognito' toggle — but most sellers don't need to.
The marketplace is showing a CAPTCHA
If Poshmark or Mercari served you a 'prove you're human' page, the extension pauses and notifies Closo. You'll see a yellow badge on that marketplace in your dashboard. Solve the CAPTCHA in your normal browser tab, and the extension resumes on its next cycle.
Chrome is fully closed
Chrome must be open for the extension to run background refreshes. If you close Chrome overnight, your sessions can expire by morning. We recommend leaving Chrome open or starting it once a day.

A note on speed

Most crosslists complete in under 60 seconds — for a single product to 4 marketplaces. Bulk operations (delisting 50 items, importing a closet) take longer because each marketplace has rate limits. We respect those limits to keep your account in good standing — flooding Poshmark with 100 deletes in 10 seconds is the fastest way to get flagged.

If something is taking longer than expected, check your Marketplaces page. A yellow or red badge there is the most common reason. Resolving the badge usually means the queue starts moving again.

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