Proxy Glossary
Every key proxy term, defined in plain English. Bookmark this page and jump to any letter — no jargon, no assumed knowledge.
A
Anti-bot system
Software that detects and blocks automated traffic using signals like IP reputation, request rate and browser fingerprint. Quality residential or mobile IPs help legitimate traffic pass these checks.
ASN (Autonomous System Number)
A unique ID for a network operator on the internet. Anti-bot systems use the ASN behind an IP to tell datacenter ranges apart from residential ISPs.
B
Backconnect proxy
A single gateway endpoint that automatically routes each request to a different IP from a pool, so you don't manage individual addresses. Common with rotating residential proxies.
Bandwidth
The amount of data transferred through a proxy, usually measured in gigabytes (GB). Residential and mobile proxies are typically billed by bandwidth.
C
CAPTCHA
A challenge designed to tell humans from bots. Frequent CAPTCHAs usually mean your IP reputation, pace or fingerprint has raised suspicion.
CGNAT (Carrier-Grade NAT)
The technology that lets mobile carriers share one public IP among thousands of users. It's why mobile proxies are so hard to block.
Concurrency
The number of simultaneous connections or threads you run. Higher concurrency speeds up jobs but raises the risk of rate-limiting if not paced well.
D
Datacenter proxy
An IPv4 proxy hosted in a data centre rather than on a home connection. Fast and cheap, but recognisable to strict anti-bot systems. See residential vs datacenter.
Dedicated proxy
An IP reserved for your exclusive use, not shared with other customers. Ideal for stable, account-based work where a consistent identity matters.
F
Fingerprint (browser fingerprint)
The combination of attributes — User-Agent, headers, TLS signature, screen and timezone — that identifies a client. A clean IP with a bot-like fingerprint can still be blocked.
G
Gateway
The host and port you connect to that forwards your traffic into a proxy network. With backconnect proxies, the gateway handles IP rotation for you.
Geo-targeting
Selecting proxy IPs in a specific country, region, city or carrier so a website serves you localized content. Essential for ad verification and market research.
H
HTTP / HTTPS proxy
A proxy that handles web traffic. HTTP covers standard requests; HTTPS tunnels encrypted connections. Nearly all modern proxies support both.
I
IP address
A unique address identifying a device on a network, so data can be routed to it. Proxies swap your IP for one of theirs.
IPv4
The dominant internet addressing format (e.g. 192.0.2.45), with about 4.3 billion addresses. Scarce and widely trusted — the focus of this site. See what is an IPv4 proxy.
IPv6
The newer addressing format with a vastly larger space. Cheaper at scale but less universally trusted than IPv4 by anti-bot systems.
ISP proxy (static residential)
A proxy hosted in a data centre but registered to a real ISP, blending datacenter speed with residential-level trust. Usually static IPv4.
L
Latency
The delay between sending a request and receiving a response. Datacenter and ISP proxies generally have the lowest latency.
M
Mobile proxy
A proxy using a 4G/5G carrier IP. The hardest type to block thanks to CGNAT, but the most expensive. Read the mobile proxies guide.
P
Pool
The total set of IP addresses a provider can route your traffic through. Larger, fresher pools generally mean fewer repeated IPs and fewer blocks.
Port
A numbered endpoint on the proxy server you connect to alongside the host. Different ports may map to different proxy types or rotation behaviours.
Protocol
The rules a proxy uses to carry traffic — HTTP, HTTPS or SOCKS5. See our homepage section on proxy protocols.
Proxy server
An intermediary computer that forwards your requests using its own IP, hiding your real address from the destination.
R
Rate limiting
A site's cap on how many requests it accepts in a time window. Exceeding it triggers errors or blocks — pace your requests to stay under it.
Residential proxy
A proxy using a real IPv4 address from a home ISP. Highly trusted and ideal for strict targets, billed by bandwidth.
Rotating proxy
A proxy that assigns a new IP per request or on a timer — perfect for spreading large scraping jobs across many addresses.
S
SOCKS5
A flexible, protocol-agnostic proxy standard that can route any traffic — not just web. Favoured for non-web tools and high-concurrency work.
Static (sticky) proxy
A proxy that keeps the same IP for a session or indefinitely. Essential for logins, carts and account management.
Subnet
A block of related IP addresses. Sites sometimes block whole subnets, so pool diversity across subnets matters for resilience.
Success rate
The share of requests that return valid data. The single most useful metric for judging real proxy performance on your targets.
T
Time-to-first-byte (TTFB)
How long it takes to receive the first byte of a response — a core speed measure we record in our testing.
Transparent proxy
A proxy that forwards traffic without hiding that a proxy is in use (and may reveal your IP). For privacy and scraping you want anonymous/elite proxies instead.
U
User-Agent
A header that tells a site what browser/device you're using. Consistent, realistic User-Agents help requests look human.
V
VPN vs proxy
A VPN encrypts all device traffic through one provider for privacy; proxies are configured per-app/per-request and built for scale and IP rotation.
W
Whitelisting (IP authentication)
Authorising your own IP in the provider dashboard so the proxy trusts you without a password. Convenient on a fixed connection.
Now put it into practice
See the 15 best proxy providers of 2026, ranked by hands-on testing — with our top value pick on top.