Proxies for Playwright
The library gives you two levers most tools do not: an address per context and full control over what the page is allowed to fetch.
One address per context
Contexts are isolated, so each can carry its own address. That makes parallel work with different identities straightforward.
Keep the mapping explicit and log it, because debugging a mixed-up context is unpleasant.
Interception cuts the traffic
Route handlers let you abort requests for images, fonts and advertising before they leave. The saving is measured in multiples.
Memory sets the ceiling
Each context costs memory. On a machine with sixteen gigabytes, around twenty contexts is a sensible upper limit.
Past that the machine starts swapping and the run slows down for reasons that have nothing to do with the network.
Close what you open
Contexts left open leak steadily. Long runs die overnight from this more often than from any network problem.
ctx = browser.new_context(proxy={"server": PROXY})
ctx.route("**/*.{png,jpg,woff2}", lambda r: r.abort())