Network

What is Bandwidth?

Bandwidth carries two meanings in proxy work. One is link capacity, measured in bits per second. The other is transferred volume, measured in gigabytes, and that is what proxy providers bill. Metering counts every byte crossing the proxy in both directions, including protocol overhead, headers, redirects, images and requests that end in a block.

Providers meter on the wire, which shapes how you should think about the bill. Compressed responses are counted at their compressed size, so sending Accept-Encoding with gzip or brotli and honouring the result cuts consumption on text-heavy targets substantially. Upload counts too, which shows up on POST-heavy automation and file submissions. Header overhead is small per request and large across millions of them, particularly when a client sends a long cookie jar to every endpoint on a domain.

Page composition drives the number more than request count does. A JSON endpoint returns a few kilobytes; the same data rendered as a full page in a headless browser pulls stylesheets, webfonts, tracking scripts, hero images and sometimes video, which commonly runs into single-digit megabytes per load. Request interception is the standard remedy: abort image, media and font requests in Playwright or Puppeteer before they leave, or skip the browser entirely and call the API the page itself calls.

Your own counters and the provider dashboard will disagree, and the reasons are mechanical. A CONNECT tunnel is opaque, so the proxy counts encrypted bytes it cannot inspect while your client sees decompressed content. Blocked pages, CAPTCHA challenges and error responses still transfer data. Every retry pays again. Run a pilot crawl of a few hundred pages, divide measured consumption by pages completed, and use that cost-per-page figure to forecast rather than an estimate from response sizes.

Billing models follow from all this. Per-GB pricing makes consumption the only variable to manage, which suits teams that can control what their clients download. Port or subscription rentals fix a monthly cost and leave throughput open, which suits steady long-running sessions. PROXIES.SX bills bandwidth alone, from $4/GB down to $2.40/GB at volume, with no charge for endpoints, rotation or support and no expiry on the gigabytes you buy, so trimming what your crawler downloads goes straight to the invoice.

Where you meet it

Bandwidth becomes an operational question when a crawl that looked cheap in a test run turns into an unexpected invoice at scale. Before scaling, measure what one page costs through your actual client, then look at what you are downloading and cannot use. Blocking images, media and fonts in a headless browser removes the largest part of most page loads, which changes the economics of the whole job.

Common questions

How much bandwidth does scraping one page use?

It depends entirely on how you fetch it. A JSON API response is often a few kilobytes, a plain HTML fetch tens to hundreds of kilobytes, and a full browser page load with assets frequently runs into megabytes. Measure a sample of your own targets rather than working from an average.

Is bandwidth the same as connection speed?

No. Capacity describes how much data a link can carry per second, while proxy billing refers to the total volume transferred over time. A fast connection and a small bill are compatible: what you pay for is the number of bytes moved, not how quickly they moved.

How do I reduce proxy bandwidth usage?

Request compressed responses, block images, fonts and media in headless browsers, call underlying JSON endpoints instead of rendering pages, and cache anything you fetch more than once. Stop retrying targets that are hard-blocking you, since every failed attempt still transfers billable data.

Related terms

Latency
Latency is the delay between sending a request and receiving the first byte back, measured as round-trip time in milliseconds. Through a proxy it spans the client's hop out, the proxy's hop to the target and the return leg. A mobile exit adds more delay than a datacenter one, since radio scheduling and carrier NAT sit in the path.
IP Address
An IP address is the numeric identifier a device presents on an IP network so packets can be routed to and from it. IPv4 writes 32 bits as four decimal octets, such as 203.0.113.7. IPv6 writes 128 bits as hexadecimal groups, such as 2001:db8::1. Every request a server logs is tied to one.
IPv4
IPv4 is version 4 of the Internet Protocol, addressing hosts with 32 bits written as four dot-separated octets, which gives roughly 4.3 billion addresses. The top-level pool ran dry in 2011, pushing providers toward private addressing, carrier-grade NAT and a paid transfer market. Nearly all proxy traffic still runs over IPv4 because that is what target sites accept.
IPv6
IPv6 is version 6 of the Internet Protocol, addressing hosts with 128 bits written as eight hexadecimal groups, such as 2001:db8::1. The space is large enough that carriers assign each subscriber a whole subnet, usually a /64 or wider, so reputation systems score prefixes instead of single addresses. Adoption is broad but far from universal.
CGNAT
Carrier-grade NAT is address translation performed by an ISP rather than in the customer's router, putting many subscribers behind one public IPv4 address. Mobile networks depend on it. Each customer holds a private or shared-range address, usually from 100.64.0.0/10, and the carrier rewrites the source address and port on every outbound flow.
NAT
Network Address Translation rewrites the address and port fields of packets as they cross a router, letting many private hosts share one public IP. The router keeps a translation table, mapping each outbound flow to a free public port and reversing the rewrite on replies. Home routers do this for a household; carriers do it for whole regions.
ASN
An Autonomous System Number identifies a network that announces its own IP address ranges to the rest of the internet through BGP. Every routable address sits inside a prefix announced by some AS, so the ASN behind an IP tells you who operates it - a mobile carrier, a hosting provider, a home ISP or a corporate network.

Real 4G/5G mobile and residential IPs

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