Feature Spotlight: What Massive's ISP Proxies Actually Give You

Massive's ISP proxies are rotating US proxies on AT&T infrastructure, with 10 Gbps connectivity and sticky sessions that hold the same IP until you change the session ID. They sit between datacenter and residential. They typically run steadier than a real consumer device, and their IPs are registered to an ISP rather than a cloud host. This spotlight covers what they do, the limits you should know before building on them, and how they compare with Massive's residential network.

Key Takeaways

• Massive ISP proxies run on AT&T infrastructure in the US, at 10 Gbps, over HTTP, HTTPS, and SOCKS5 (Massive Docs).
• Sticky sessions have no fixed expiry. Reuse a session ID and you keep the same IP. Leave it out and the IP rotates automatically.
• There's no geotargeting yet, and only ports 80 and 443 are reachable. Use residential when you need a specific country, region, city, or ZIP code.

What are ISP proxies, and why do teams use them?

ISP proxies are IP addresses registered to an internet service provider but served from infrastructure built for speed. Teams typically reach for them where they would otherwise use datacenter IPs: high-volume jobs that need speed and stable addresses, without the cloud-provider label.

The appeal is simple. Many sites treat cloud-hosted IP ranges with suspicion, because a large share of automated traffic comes from them. In its 2025 Radar Year in Review, Cloudflare reported that Amazon Web Services and Google Cloud originated a quarter of global bot traffic on its network (Cloudflare, 2025). We covered what that means for agents in why AI agents get blocked on datacenter IPs. An IP that belongs to an ISP doesn't sit in those cloud ranges. And unlike a residential device, it isn't somebody's phone that might go offline when they walk into an elevator. The tradeoff: you give up the geographic spread and device variety of a residential network, and you get consistency in return.

What does Massive's ISP network include?

Per the ISP Proxies introduction, Massive's ISP network runs on AT&T infrastructure with US coverage, 10 Gbps speeds, and automatic IP rotation. It supports HTTP, HTTPS, and SOCKS5.

The connection details:

With your proxy username and API key exported as PROXY_USER and API_KEY, a first request looks like this:

curl ip-api.com \
  -x isp.joinmassive.com:8000 \
  -U "$PROXY_USER:$API_KEY"

Run it twice and you'll typically see two different IPs, because requests without a session ID rotate.

How do sticky sessions work on ISP proxies?

Add -session-{ID} to your username, and every request with that ID goes out through the same IP. The ID can be any string up to 255 characters. According to the ISP sticky sessions docs, "Sessions continue indefinitely unless the session identifier is changed."

U="$PROXY_USER-session-37"
curl ip-api.com \
  -x isp.joinmassive.com:8000 \
  -U "$U:$API_KEY"

That "indefinitely" is the headline feature, and it's a different model from residential. On Massive's residential network, sessions use a fixed TTL: 15 minutes by default, adjustable from 1 to 1,440 minutes, and not extended by later requests (Residential sticky sessions). A residential session is tied to a real device that can go offline. An ISP session isn't, so it can simply keep going.

That makes ISP proxies a natural fit for work where the IP needs to stay put: a multi-step checkout test, a long-running monitoring job against one site, or any flow where a mid-task IP change would reset state.

In Python, the same session looks like this:

import os
import requests

user = os.environ["PROXY_USER"]
user += "-session-37"
key = os.environ["API_KEY"]
host = "isp.joinmassive.com"
port = 8000
url = "http://ip-api.com/json"

proxy = (
    f"http://{user}:{key}"
    f"@{host}:{port}"
)
proxies = {
    "http": proxy,
    "https": proxy,
}

for _ in range(3):
    r = requests.get(
        url,
        proxies=proxies,
        timeout=30,
    )
    # same IP each time
    print(r.json()["query"])

Change 37 to a new value when you want a fresh IP for the next task.

The limits of Massive's ISP proxies

The constraints are specific, and it's better to know them before you build. Per the ISP usage restrictions:

• Ports 80 and 443 only. Other ports return 453 Port Forbidden.
• UDP is restricted by default. Contact support if you need it.
• Port 25 is closed. No outbound email.
• Restricted content is blocked. Requests that break content policy return 452 Disallowed Content. Legitimate users who need restricted categories can complete KYC with support.
• No geotargeting (yet). The ISP geotargeting page says plainly: "We do not support geo-targeting for ISP proxies yet."

That last point is the one that decides most choices. If your job depends on seeing a page as a user in Munich or Osaka would, ISP proxies aren't the tool.

ISP or residential: which should you use?

Pick ISP proxies for US workloads that need throughput and long, stable sessions. Pick residential when you need location precision or the variety of real consumer devices. Massive's residential network spans more than 1,000,000 opted-in devices in 195+ countries (Residential introduction), with targeting by country, subdivision, city, or ZIP code.

You don't have to pick one. You can route US bulk jobs through ISP and send anything location-specific to residential. Both use the same {PROXY_USERNAME}:{API_KEY} credentials, so the client code stays the same. What changes is the endpoint (isp.joinmassive.com on 8000/4080 versus network.joinmassive.com on 65534/65535) and the username parameters: residential sessions can add -sessionttl-{minutes} and a session mode, plus geo keys like -country-US. For more on splitting traffic this way, see the multi-provider proxy strategy and residential vs. datacenter proxies for AI agents.

How do I get started with ISP proxies?

Getting a first request through takes three steps:

1. Pick your port. Point your client at isp.joinmassive.com on 8000 (HTTP or SOCKS5) or 4080 (HTTPS), per the ISP authentication docs.
2. Run the curl check above with your username and API key, and confirm the IP changes between requests.
3. Add -session-{ID} only to the steps that need a stable IP.

The docs include ready-made samples for Python, Scrapy, Puppeteer, Ruby, and .NET, and the full list of error codes is on the ISP error types page. For why device count matters more than IP count on the residential side, see why more IPs doesn't mean a better proxy network.

ISP proxies: the bottom line

• AT&T-backed, US-only, 10 Gbps, HTTP/HTTPS/SOCKS5.
• Sticky sessions hold the same IP until you change the session ID.
• Only ports 80 and 443 are reachable, and there's no geotargeting, so anything that depends on location belongs on residential.
• Use ISP for steady US throughput.

Sources

• Massive Docs, "ISP Proxies introduction"
• Massive Docs, "ISP sticky sessions"
• Massive Docs, "ISP usage restrictions"
• Massive Docs, "ISP geotargeting"
• Massive Docs, "Residential introduction"
• Massive Docs, "Residential geotargeting"
• Massive Docs, "Residential sticky sessions"
• Cloudflare, "The 2025 Cloudflare Radar Year in Review"