A page is slow, or uses a lot of data

Why a page can be heavy

Every price, book and rate on the site is the exchanges’ own public market data, read by your browser, which does every sum itself as the figures arrive. Each exchange you switch on is a connection of its own: some send every change as it happens, the others are asked every few seconds. The more exchanges, the more there is to read and to draw.

Pages that read every exchange

The scoreboards, the exchanges’ pages, Signals and the futures and options pages read every exchange of their kind while they’re open, whichever you have on, so they’re the heaviest. On the scoreboards, the exchanges’ pages and Signals, switch on Only exchanges I use and they read only yours.

Making it lighter

• Switch off the exchanges you don’t use in the header’s exchange switch: choosing exchanges.
• Close the site’s other tabs: each keeps its own connections.
• Leave Market Cap & 24h chart off over an index’s table when you don’t need it: its lines are fetched as their rows come into view.
• On a slower device, switch off Flash prices as they change in Settings: there’s less to draw.

What the site does already

Most exchanges’ code loads only once you switch them on. An index’s table is drawn again at most every second, however fast the prices come. A page that reads many exchanges keeps reading for 60 seconds in a background tab, then stops until you come back, unless Signals’ alerts are on. Find a coin’s list reads its figures only while it’s open.

Still slow?

If one exchange keeps reconnecting, or a page stays slow with few exchanges on, report it with the page’s address, and what Connection diagnostics shows with ?debug added to a coin page’s address: an exchange that won’t connect explains it.