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.

Chrome Web Store: coming soonFirefox Add-ons: coming soonOpen crypto compare tool
Examples to select
BTCETHSolanaXRPDogecoin
Crypto market cap
Latest available crypto price
Rank when available
Coin battle comparison links
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.

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

Browse the other Marketcaper extension pages

View extension hub