IPv4 and IPv6 are two versions of the internet protocol, but the practical difference is simple: IPv4 has a limited address supply, while IPv6 has an enormous one. IPv4 uses 32-bit addresses and still has the widest compatibility across the web. IPv6 uses 128-bit addresses, which makes addresses far more abundant and usually much cheaper for proxy use.
For most users, IPv4 vs IPv6 is not a speed question. It is a compatibility question. IPv6 can be a strong choice for high-volume scraping, automation, and parallel workloads, but only when the target site supports it. IPv4 remains the safer default for legacy sites, trust-sensitive tasks, and any workload where broad reach matters more than cost per IP.
IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses. That massive address-space difference is the reason IPv6 exists.
For everyday browsing and scraping, IPv4 and IPv6 perform similarly. Network quality, proxy location, and the target website usually matter more than the protocol itself.
IPv6 proxies are usually much cheaper because IPv6 addresses are far more abundant. That makes them useful for large-scale, cost-sensitive workloads.
IPv4 proxies still offer the broadest compatibility because many websites and services remain IPv4-only or only partially support IPv6.
For proxy buyers, the best choice depends on the target. Use IPv6 when the site supports it and volume matters; use IPv4 when compatibility, account trust, or reputation matters more.
IPv4 came first and uses short 32-bit dotted decimal addresses. IPv6 is the newer version, with longer 128-bit hexadecimal addresses, a much larger supply, simpler routing, and built-in IPsec support. The two are not directly interchangeable, so there is no backward compatibility between them, but most networks run both side by side through dual-stack. Above the IP layer, the transport layer is unchanged: TCP and the User Datagram Protocol (UDP) work the same over both versions. The following table sums up the key differences between the two protocols.
| Attribute | IPv4 | IPv6 |
|---|---|---|
| Address length | 32-bit | 128-bit |
| Format | Dotted decimal (192.0.2.1) | Hexadecimal, colon-separated (2001:db8::1) |
| Total addresses | ~4.3 billion | ~3.4 x 10^38 |
| Configuration | Manual or DHCP | SLAAC or DHCPv6 |
| Packet header | Variable length, more fields | Fixed 40-byte, simplified |
| Built-in security | Optional, IPsec retrofitted | IPsec defined in the standard |
| NAT | Commonly required | Usually unneeded |
| Site support (2026) | Near-universal | Partial; roughly half of major traffic |
If you are weighing this against the wider market, our guide to the different proxy types covers how residential, mobile, datacenter, and ISP options compare.
The two protocols differ at the IP layer, and a handful of those differences carry real consequences.
IPv4's roughly 4.3 billion addresses sounded like plenty in the early 1980s, but the rising number of devices connected to the internet, from mobile networks to IoT devices, drained the available IP addresses. Regional pools ran dry. ARIN, the registry for North America, depleted its general IPv4 free pool on 24 September 2015. IPv6's 128-bit address space (about 3.4 x 10^38 addresses) was designed to remove that ceiling, one of the significant benefits it offers, leaving room for decades of future growth.
To stretch a limited supply, IPv4 leans on network address translation (NAT), which lets many devices on a local network share one public IP address. IPv6 has enough addresses to give every device its own unique IP address, so it is built for end-to-end connectivity and usually needs no NAT. Its fixed 40-byte IP header is simpler than IPv4's variable packet header, which keeps the header size predictable, removes the header checksum field that IPv4 carries, and turns IPv4's TTL value into the hop limit in IPv6. When a packet size is too large for a link, IPv4 routers can split it using the fragment offset field, while IPv6 handles packet fragmentation only at the source. Together, these changes keep per-hop work down and support more efficient routing.
IPsec is defined within the IPv6 standard, while in IPv4 it was retrofitted as an add-on. That does not make IPv6 secure by default. IPsec still has to be configured either way, so the security features you get depend on how the network is set up, not on the protocol version alone.
For typical browsing, the speed difference is negligible. IPv6 can route more efficiently in some conditions, thanks to its simpler header and lack of NAT, but you should not expect a noticeable everyday speed gain from switching protocols.
Adoption is the real gap. Google's live IPv6 statistics, which measure the share of its users connecting over IPv6, passed 50% for the first time in March 2026 and now sit near that mark, running higher on weekends. Because vendor figures often conflict, Google's IPv6 data is the cleanest public benchmark to check on any given day. Adoption also varies widely by country, from leaders like France and India to single-digit figures elsewhere. Until coverage is universal, datacenter IPv4 proxies reach every target, while IPv6 covers the growing share of sites that support it.
There is one rule that settles most of these decisions: choose by the site you are hitting, not by the protocol. Cost and pool size only matter after the target supports IPv6. Work through three questions in order.
Does the target publish IPv6 (AAAA) DNS records? If no, use IPv4 (or reach it from IPv6 through NAT64/DNS64). If yes, continue.
Is the workload trust-sensitive (accounts, payments, logins)? If yes, lean toward IPv4 with residential or ISP IPs. If no, continue.
Is the job high-volume and cost-sensitive? If yes, IPv6 wins. If it is a mix, run dual-stack and split the traffic.
That logic maps cleanly onto specific workloads:
| Workload | Best fit | Why |
|---|---|---|
| Bulk scraping of IPv6-ready targets | Datacenter IPv6 | Huge pool, lowest cost per IP |
| Account management, payments, social logins | Static Residential / ISP (IPv4) | Mature IP reputation |
| Mixed automation stack | Dual-stack | Trust-sensitive over IPv4, bulk over IPv6 |
| Legacy or IPv4-only sites | IPv4 | No IPv6 record to connect to |
| Large parallel jobs on modern targets | IPv6 | About 83% cheaper per proxy at Proxy-Cheap |
For trust-sensitive work, static residential proxies and ISP proxies provide IPv4 addresses with established IP reputations. For high-volume collection that does not require that level of maturity, rotating residential proxies spread requests across a large pool.
For proxies, IPv6's advantage is cost and pool size, because IPv6 addresses are abundant. The catch is compatibility, since only part of the web accepts IPv6 today. IPv4 proxies cost more but connect almost everywhere and carry more mature IP reputation. The right pick depends on whether your target supports IPv6 and how trust-sensitive the task is.
Cost. At Proxy-Cheap, Datacenter IPv6 proxies start at $0.20 per proxy while Datacenter IPv4 starts at $1.18, so IPv6 runs about 83% cheaper per IP (check the live product pages for current pricing). For large parallel jobs, that gap adds up fast, which is why cost-driven workloads on modern targets lean IPv6. If your work needs the older protocol instead, you can buy IPv4 proxies priced per IP.
Compatibility. Many large targets are still IPv4-only. Without an IPv6 (AAAA) record, an IPv6 proxy has nothing to connect to unless you route through NAT64/DNS64. That is why IPv4 stays the safe default when you do not control the target.
Reputation and detection. IPv4 pools are more established, so they tend to support a high request success rate on trust-sensitive tasks where IP reputation carries weight. IPv6's large, fresh ranges have less detection history, which suits high-volume work on compatible sites. For web scraping specifically, IPv4 proxies are still the popular default, as Scrapfly notes, with IPv6 winning on cost when the target cooperates. Large collection projects often mix the two: see our large-scale data scraping use case for how that plays out.
Both protocols sit under one pay-as-you-go account at Proxy-Cheap, so you can prototype on one and scale onto the other without onboarding a second vendor. Running modern, IPv6-ready targets at volume? Datacenter IPv6 proxies start at a fraction of IPv4 pricing. Hitting legacy or IPv4-only sites? Datacenter IPv4 covers those with high compatibility. Both run on the same account.
IPv4 (Internet Protocol version 4) is the fourth internet protocol version and still the most widely used. The Internet Engineering Task Force first defined it in RFC 791 in 1981. IPv4 uses 32-bit addresses written in dotted decimal notation, four numbers from 0 to 255 separated by dots, like 192.0.2.1. That format allows about 4.3 billion unique addresses.
In the early internet, addresses were handed out in fixed address classes (A, B, and C), later replaced by CIDR and variable length subnet masking (VLSM) for more efficient use of address ranges. IPv4 also reserves private addresses for internal networks (for example 192.168.0.0), a loopback address (127.0.0.1) for a single device to reach itself, and ranges for broadcast communication across a local network.
The 4.3 billion ceiling ran short as connected devices, mobile networks, and IoT devices multiplied. Two workarounds keep IPv4 going: network address translation (NAT), which lets many devices share one public IP address, and CIDR, which slices address ranges more precisely. These extend the supply but do not remove the limit.
IPv4 still carries most internet traffic and underpins many proxy products, including mobile proxies that route through real 3G/4G/5G mobile networks. For the full specification, see RFC 791.
IPv6 (Internet Protocol version 6) is the latest version of the internet protocol and the long-term successor to IPv4. The IETF specified the current standard in RFC 8200 in 2017. IPv6 uses 128-bit addresses written in hexadecimal, eight groups of four hexadecimal digits separated by colons, like 2001:db8::1 (consecutive zero groups can be shortened with a double colon). That expanded address space holds about 3.4 x 10^38 addresses, enough to give every internet-enabled device its own unique public IP address with room for future growth.
IPv6 brings several design changes. SLAAC (stateless address autoconfiguration) lets a device set up its own IP address without manual configuration or a Dynamic Host Configuration Protocol (DHCP) server, though DHCPv6 is still available. The packet header is a fixed 40 bytes with a Next Header field and optional extension headers, instead of IPv4's variable header. A flow label field supports packet flow identification for traffic that needs consistent handling. IPv6 also drops broadcast communication in favor of multicast and anycast addresses, and supports temporary addresses for added privacy.
There is no backward compatibility with IPv4: the two protocols cannot talk to each other directly. IPv6 is the long-term replacement, but for now it coexists with IPv4 through dual-stack. For the full specification, see RFC 8200.
Yes. Because adoption is partial, the two protocols are designed to run side by side, and most networks use more than one method to connect them.
Dual-stack is the most common approach: a device or server runs both IPv4 and IPv6 at the same time and uses whichever the other end supports. Tunnelling carries IPv6 packets inside IPv4 (or the reverse) across networks that speak only one version. NAT64 paired with DNS64 lets an IPv6-only client reach an IPv4-only target by translating between the two, which matters when an IPv6 proxy needs to connect to a site that has no AAAA record.
For proxy buyers, the practical takeaway is that you do not have to pick one protocol forever. You can start on whichever fits today's targets and add the other as your needs change. High-volume work often pairs both, running bulk collection over IPv6 while keeping IPv4 for sites that need it. Products built for high throughput, such as unlimited-bandwidth proxies, make that mixed setup easier to scale.
