How to use
Username Inspector

Username Inspector has three tools. All are free and none needs an account.

I want to...	Use	Go to
See if a username or store name is free on a few platforms and get an answer right away	Username checker, auto-check mode	Auto-check
Check many names, or platforms that block automatic checks	Username checker, manual mode	Manual mode
Find out what a sale pays out after fees	Fee calculator	Fee calculator
Let an AI assistant do either of those for me	MCP server	MCP server

Auto-check is the default mode on the home page. It looks the name up for you and shows a live result where a platform allows it, with a link to check by hand where it doesn't.

1. Enter up to 5 usernames in the box, separated by commas or new lines.
2. Select your platforms. eBay is ticked by default. The platforms marked with an asterisk (Depop, Etsy, Mercari, Ruby Lane) can't be checked automatically, so they appear as links.
3. Leave Mode on "Auto-check up to 5 usernames".
4. Click Check Availability, or press Enter in the box.
5. Each row first shows Checking, then updates on its own within a few seconds.

What auto-check can and can't do

• Tried live: eBay, eBay Store, Poshmark, Grailed, Vinted, Whatnot, Bonanza, and Chairish.
• Most reliable: Poshmark, Vinted, and Bonanza usually return a live result. eBay, eBay Store, Grailed, Whatnot, and Chairish often block automated lookups, and then the row shows a "Check manually" link. This can change as platforms change their protection.
• Link only: Depop, Etsy, Mercari, and Ruby Lane. Their bot protection blocks automatic checks, so each shows a "Check manually" link.
• Limit: 5 usernames per check. Enter more and the site asks you to switch to manual mode.
• If a platform blocks the check, that row shows Manual with a link, rather than guessing. If the check service is unavailable, every row falls back to links.
• Repeat checks are instant. The same check in the same browser tab reuses its result for 5 minutes.

After the results appear

• On an Available row, click the link to start selling or sign up on that platform.
• On a Taken row, click "View on..." to see who has the name.
• Each username also gets a Domain row that checks the matching .com.
• Share copies a link to the same check. It re-runs the check when opened, so the answer is current.

Open All Tabs and Export CSV only appear in manual mode.

Manual mode builds the profile link for every username and platform you pick, and you open them to see for yourself. It handles big batches and every platform, including the four that auto-check can't reach.

1. Enter up to 500 usernames, separated by commas or new lines.
2. Select your platforms.
3. Under Mode, choose "Manually check up to 500 usernames".
4. Click Check Availability. You get a list of links, one per username and platform. Nothing is looked up, so every row is marked Manual.
5. Open each link. A profile page means the name is taken. A "not found" or error page means it is free. (On eBay, a page that says "Sorry, this user was not found" means free.)

Manual mode tools

• Open All Tabs opens every link in its own tab, a fraction of a second apart. Browsers may block some tabs, so the site asks you to confirm when there are more than 20.
• Export CSV downloads a spreadsheet with the columns Username, Platform, and URL, handy for tracking a long list.
• Share copies a link that reopens the same names, platforms, and mode.

Auto-check or manual?

	Auto-check	Manual
Usernames per check	Up to 5	Up to 500
Result	Live Available or Taken	A link to open yourself
Platforms	Up to 8 tried live (3 most reliable), 4 as links	All, as links
Speed	A few seconds, no tabs	As fast as you open the links
Extras	Share	Open All Tabs, Export CSV, Share

You see	It means	What to do
Checking	The lookup is still running.	Wait a moment. Rows update on their own.
Available	No profile was found for that name on that platform.	Claim it soon, using the link on the row.
Taken	A profile with that name exists.	Try a variation, or open the link to see the account.
Manual	The platform can't be checked automatically, or the check was blocked.	Open the link and look at the page yourself.

Good to know

• Available isn't a reservation. A name can still be refused at sign-up if the platform reserves or blocks it. Register as soon as you decide.
• Names are cleaned up for you. Spaces and symbols are removed, and a name must be 3 to 50 characters of letters, numbers, hyphens, or underscores.
• Check every platform you plan to use, so your name matches everywhere. Our guide to what to do when your username is taken has ideas when it isn't free.

The fee calculator shows what a sale pays out on eBay, Poshmark, Mercari, Depop, Etsy, Grailed, and Vinted, side by side. Everything is worked out in your browser.

1. Sale price: the item price before shipping. This is the only required field.
2. Shipping charged to buyer (optional): what the buyer pays you for shipping. eBay, Etsy, Depop, and Mercari take fees on it. Poshmark and Vinted ignore it, because the buyer pays the label there. If you offer free shipping, leave it blank.
3. Item cost (optional): what you paid for the item. Adding it unlocks profit, margin, and ROI.
4. Your shipping cost (optional): the postage you pay. Not used for Poshmark or Vinted.
5. eBay promoted listing rate (optional): your ad rate as a percent. It only affects eBay.
6. Click Calculate fees, or press Enter.

Reading the table

Each platform gets a row with its fee breakdown, total fees, and You keep (the sale price plus shipping charged, minus fees). If you entered an item cost or a shipping cost, three more columns appear: Profit, Margin (profit as a share of price plus shipping charged), and ROI (profit as a share of what you paid).

Example: a $50 item with $8 shipping charged and a $10 cost. On eBay the fees come to $8.29, you keep $49.71, and profit is $39.71. On Poshmark the fee is $10.00, you keep $40.00, and profit is $30.00, because the buyer pays shipping there.

Share a result

Copy link to these results copies a link that reopens the same numbers, for example /fee-calculator/?price=50&ship=8&cost=10. The address bar updates after every calculation, so you can also copy it directly. The link accepts these values: price, ship (shipping charged), cost (item cost), postage (your shipping cost), and promo (eBay ad rate).

Also in our guides

The fee guides for eBay, Poshmark, Depop, Etsy, and the comparison each have a small calculator at the top, so you can try your own numbers without leaving the article.

What the numbers don't include

• Sales tax.
• Category exceptions and store subscriptions. The calculator uses each platform's standard US rate. Etsy's $0.20 listing fee is counted once per sale.
• Rates change. The page shows when rates were last verified, with links to each platform's own fee page.

If you use an AI assistant that supports remote MCP servers, you can give it both tools above and ask in plain language. It is free and needs no key. The full reference, with limits, accuracy notes, and privacy details, is on the MCP server page.

1. Add the server to your assistant using this URL: https://usernameinspector.com/api/mcp. In Claude Code, run claude mcp add --transport http username-inspector https://usernameinspector.com/api/mcp. For clients with a JSON config, add the URL under mcpServers. For clients with a custom connector option, paste the URL.
2. Ask a question. For example: "Is thriftlane free on Poshmark and eBay?" or "I sell a jacket for $85 with $9 shipping that cost me $22. Where do I keep the most?"
3. Read the answer. The assistant calls check_username or compare_fees and reports back. Results marked unverified come with a link to check by hand.

The tools behave like the website: check_username matches auto-check (the same platforms tried live, the same 4 as links), and compare_fees uses the same rates as the calculator. It is rate-limited, so ask for one name at a time.

A platform shows "Manual" in auto-check

Depop, Etsy, Mercari, and Ruby Lane always do, because they block automatic checks. For the others, Manual means the platform blocked or failed that check, which is common for eBay, Grailed, Whatnot, and Chairish. Click "Check manually" to see the profile page yourself, or try again in a minute.

"Auto-check supports up to 5 usernames"

Switch Mode to "Manually check up to 500 usernames" and run it again.

My username changed after I typed it

Spaces and symbols are stripped, and only letters, numbers, hyphens, and underscores are kept. If nothing valid is left, the site asks you to enter a different name.

The result doesn't match what I see on the platform

Results come from each platform's public profile page at that moment. Names can be reserved, banned, or released between checks. Treat Available as a strong signal, then confirm at sign-up.

The calculator's numbers don't match the platform's

Check the "rates last verified" date, and whether your category or store plan has different rates. If a rate looks wrong, report it.

Something else

See the FAQ, or contact us.