How it works
Select, click, compare by size
1
Select crypto text on a webpage.
2
Click the Marketcaper icon or right-click lookup action.
3
Open crypto market cap, latest available price, and rank where available. and compare links.
Crypto extension
Crypto market cap browser extension
Highlight crypto symbols or coin names while browsing and open a Marketcaper card with latest available market cap, price, rank, and comparison links.
Examples to select
BTCETHSolanaXRPDogecoin
Crypto market cap
Latest available crypto price
Rank when available
Coin battle comparison links
Lookup card
Marketcaper Crypto Market Cap Lookup
M
crypto catalogue
BTC
Crypto market cap, latest available price, and rank where available.
Compare by sizeOpen asset
What it does
One clear lookup purpose
The Crypto extension recognizes coin symbols and crypto asset names, then shows market cap and price context without searching unrelated stock or fund catalogues.
Selected text
Local first, click to send
Selected text is inspected locally for a possible crypto catalogue match. It is sent to Marketcaper only after you click the icon or use the right-click lookup action.
Permissions
Only what the feature needs
Browser permissions support selection lookup, the context menu, saved preferences, and requests to Marketcaper. They are not used for ads or background page scraping.
Privacy
No account required
The extension does not require a Marketcaper account, does not sell selected text, and does not use selected text for advertising.
Review notes
Why the extension asks for browser permissions
Extension code is bundled in the browser package. Requests to Marketcaper return lookup data, not remote executable scripts.
Content script on webpages
Needed to place the small Marketcaper icon beside selected text. The extension filters selections locally and does not read whole pages.
Context menu
Adds the right-click Marketcaper lookup action for selected text when you prefer not to use the floating icon.
Storage
Remembers your enable or disable preference for selection detection on your browser.
Active tab and scripting
Supports the right-click fallback on the current tab when the content script needs to be loaded safely.
marketcaper.com access
Used only to request a category-scoped lookup after you click the icon or use the context-menu action.
FAQ
Questions before installing
Will the Crypto extension confuse BTC with a stock or fund ticker?
The extension sends a crypto category filter to Marketcaper, so BTC is resolved against the crypto catalogue for this package.
Can I battle two crypto coins by market cap?
Yes. The lookup card links to the crypto compare tool, where the selected coin can be compared against another crypto asset or unlocked cross-market.
Other catalogues