ISP Proxies vs Mobile Proxies: Which One to Buy

Buy ISP proxies when you need a modest number of stable identities that stay the same for weeks, and when you move enough data that per-gigabyte billing would hurt. Buy mobile proxies when your target treats mobile carrier traffic as untouchable, when you need to force a fresh IP on demand, and when your data volume per session is small.

The compressed rule: ISP proxies are priced per identity, mobile proxies are priced per byte. Work out which of those two resources you need more of and the purchase usually decides itself. Need 200 stable identities and 5 GB a month? ISP. Need 6 identities and 400 GB a month? Still ISP. Need 6 identities, 3 GB a month, and a target that hard-blocks everything except carrier IPs? Mobile earns its price.

An ISP proxy is a static IP hosted on datacenter hardware, with the address block leased from a consumer internet provider. A WHOIS lookup returns Comcast or Vodafone or Deutsche Telekom rather than a hosting company, so the first-pass ASN filter reads the request as a home connection while it runs at server speed. That IP is normally yours alone for the billing period. You are buying exclusivity plus a residential-looking registration. The ISP proxy explainer covers how those blocks get assembled.

A mobile proxy is a real SIM on a carrier network, usually 4G LTE or 5G, with your traffic exiting through the carrier's Carrier-Grade NAT pool. The public IP you present is shared, right now, with hundreds or thousands of ordinary subscribers on that same gateway. You do not own it and cannot keep it, and that is the point. You are buying deniability through crowding, plus a rotation button that hands you a different carrier IP whenever you ask. The mobile proxy explainer and the 4G and 5G breakdown go deeper on the hardware.

The whole comparison sits in that contrast. ISP sells exclusivity, mobile sells shared cover, and nearly every downstream difference in price, speed, session length and ban behaviour falls out of that one split.

Neither column is a superset of the other. ISP wins every performance and cost-per-byte row, mobile wins every "will this request be allowed at all" row. A buyer who reads only block-resistance reviews sees one column and overpays.

ISP proxies bill per IP per month, and bandwidth is usually generous or unmetered. Your bill scales with how many identities you rent, not with the traffic you push through them. Doubling request volume on a fixed set of ISP IPs costs nothing extra. Doubling identity count doubles the bill.

Mobile proxies bill one of two ways. Rotating pools charge per gigabyte, so the bill scales with bytes moved, and every retry, redirect, image and tracking script is billed. Dedicated ports charge a flat monthly fee per SIM, sometimes with a bandwidth allowance on top, and a port gives you one identity at a time, so thirty simultaneous mobile identities means thirty ports.

Published list prices in this market move constantly. As of September 2026, mobile per-gigabyte rates and dedicated port fees vary by more than an order of magnitude between vendors, and any figure in a comparison article is a snapshot of one vendor's own rate card. Pull current numbers from each provider's pricing page before you build a model, and confirm what counts as billable traffic, because most per-GB products bill failed requests too.

A flat-rate plan makes the unit obvious. SparkProxy publishes four datacenter plans, all with unlimited bandwidth and 30 days validity: Starter at $75/month for 100 threads and 5 whitelist slots, Core at $140 for 250 threads and 10 slots, Boost at $240 for 500 threads and 15 slots, and Plus at $440 for 1000 threads and 25 slots. Nothing there gets more expensive because you moved another 200 GB. That is the structural advantage of per-IP and per-thread pricing, and it is why bandwidth-heavy jobs rarely belong on a mobile pool.

Two formulas, five minutes, and the decision stops being a matter of opinion.

ISP monthly    = identities_needed x price_per_IP_per_month
Mobile monthly = GB_per_month x price_per_GB
                 (or ports_needed x price_per_port_per_month)

Say you are quoted $3.00 per ISP IP per month and $6.00 per GB on a rotating mobile pool. Forty stable identities on ISP is $120. Whether that beats mobile depends entirely on your byte count: at 20 GB mobile is also $120 and it is a tie, at 60 GB mobile is $360, at 5 GB mobile is $30 and wins outright. The crossover is not a matter of taste, it is one division.

The input people guess wrong is the byte count. Measure it, do not assume it. Pull a representative sample of your target pages and record the real payload:

import requests

urls = [
    "https://www.sparkproxy.io/",
    "https://www.sparkproxy.io/pricing",
]

total = 0
for u in urls:
    r = requests.get(u, timeout=30)
    total += len(r.content)

avg_mb = total / len(urls) / 1_000_000
print(f"avg page {avg_mb:.2f} MB")
print(f"100k requests = {avg_mb * 100_000 / 1000:.1f} GB")

Two adjustments before you trust the output. First, plain HTML is the floor. If you render JavaScript, add the CSS, fonts, images and third-party scripts a real browser pulls, which routinely multiplies the figure several times over. Second, add your failure rate: a pool with an 80 percent success rate transfers roughly 25 percent more bytes than the successful requests alone.

Blocking images and fonts in a headless browser is the largest bandwidth lever on a metered pool. If you are running any per-GB product, do it on day one.

Mobile IPs are hard to block for a structural reason, not a technical one. Behind Carrier-Grade NAT, one public IP fronts a large block of genuine subscribers, so a site that bans that address bans paying customers along with you. Most commercial sites will not accept that trade, and apply softer controls instead: rate limits, CAPTCHAs, extra verification steps. That hesitation is the actual product you buy with mobile proxies, and no other proxy type can manufacture it.

ISP proxies clear a different hurdle. They pass the cheap first-pass ASN check that kills datacenter traffic, because the block is registered to a consumer provider. What they do not get is crowd cover. The IP is yours, its behaviour is entirely yours, and a target that flags it has flagged you specifically. That contrast against plain datacenter IPs is covered in ISP vs datacenter proxies.

Two caveats vendors gloss over. Mobile carrier ranges are well known and widely published, so a target that wants to score mobile ASNs can, and some login flows treat carrier IPs as higher risk rather than lower. And on any mature anti-bot stack, TLS fingerprint, header order and behavioural timing carry more weight than the IP class. A mobile IP with an obviously automated fingerprint still gets challenged. Buying mobile proxies to compensate for a bad client is an expensive way to not fix the client.

Bandwidth cost is the headline failure and it shows up on an invoice. Everything below shows up in your logs instead.

Throughput and concurrency are the practical ceiling. One SIM is one radio link sharing a cell with real phones, so parallel requests queue behind each other and latency swings with tower load. Jobs that run 200 concurrent connections through datacenter IPs will crawl on a mobile port.

Session stability is second. Carrier NAT reassigns addresses on its own schedule, so a long checkout, a multi-step form, or a session cookie tied to an IP can break mid-flow unless the provider offers sticky sessions and you have tested how long they hold.

Geo precision is the third. Country and carrier targeting is reliable, city-level targeting is not, because the exit gateway may sit hundreds of kilometres from the tower. If your job requires a specific metro, verify it rather than trusting the dashboard label.

And the rotating pool you buy into is not pristine. Those carrier IPs are in use right now by other customers of the same provider, including some hammering the exact target you care about. "Mobile" is not a synonym for "clean".

Supply is the first constraint. ISP blocks are leased in limited quantities, so if you need 500 distinct identities in one city, inventory gets thin and the price climbs. Mobile pools have no such ceiling, because they draw on live subscriber ranges.

Subnet clustering is the underrated one. Providers acquire ISP addresses in contiguous ranges, so fifty accounts bought from the same vendor can easily share a /24. A target that groups by subnet rather than by single IP sees fifty "different households" on one block, which is a stronger signal than any single request gives. Ask a prospective vendor how their ISP inventory is spread across ranges. The good ones answer, and the answer is worth more than the pool-size number on the homepage.

Bans are permanent in a way mobile bans are not. Static means the flag sticks to an address you keep paying for, so ask about the replacement policy before you buy: how many swaps per month, how fast, and whether a burned IP is replaced free. That criterion is almost never on a pricing page.

Exclusivity cuts both ways too. A residential-looking IP with datacenter behaviour, regular request intervals, no idle time, one user agent, is still detectable. ISP buys a clean first impression, not immunity. For where these sit next to genuine home-device IPs, see ISP vs residential proxies.

Mobile earns its premium when the target is mobile-native, or when the mobile ASN is the only class that gets through. Everywhere else, per-byte billing quietly makes it the most expensive line in the catalogue. For the wider map including residential IPs, see the three-way proxy type comparison.

Vendor benchmarks are marketing. Run your own, on your target, with a protocol tight enough to compare two products priced in different units.

1. Pick one target and write down a hard success definition. Not "HTTP 200", but "200 plus the price selector is present in the DOM". Soft blocks return 200 all day.
2. Send 500 requests through each pool with identical headers, identical concurrency, in the same time window. Changing two variables at once wastes the week.
3. Record four numbers per pool: success rate, median latency, p95 latency, total bytes transferred.
4. Re-run against the same IPs 24 hours later. Delayed bans are common and a one-hour test misses them.
5. Convert everything to one figure: monthly cost divided by successful requests per month.

Step five is the whole point. Cost per successful request is the only unit that compares a product sold by the IP against a product sold by the gigabyte. A mobile pool at a 95 percent success rate can still lose to an ISP pool at 70 percent, if the ISP pool costs a fifth as much per attempt. Most buyers never calculate it and choose on success rate alone, which overpays by default.

import requests

PROXY = "http://USER:PASS@gateway.sparkproxy.io:11000"
target = "https://www.sparkproxy.io/pricing"

ok, bytes_moved = 0, 0
for _ in range(500):
    try:
        r = requests.get(target, proxies={"http": PROXY, "https": PROXY}, timeout=30)
        bytes_moved += len(r.content)
        if r.status_code == 200 and "price" in r.text.lower():
            ok += 1
    except requests.RequestException:
        pass

print(f"success {ok/500:.1%}  transferred {bytes_moved/1_000_000:.1f} MB")

Run it against each candidate pool, plug the results into the cost formula, and the argument ends.

A large share of people shopping for ISP or mobile proxies arrived after datacenter IPs got blocked, and assumed the fix was a pricier IP class. Often the actual fix was rotation, header realism, a real TLS fingerprint, or JavaScript rendering. Price that path before committing to a metered product.

SparkProxy runs 1M+ datacenter IPs across 80+ countries, including 50,000+ US addresses, on flat unlimited-bandwidth plans. One gateway host serves all three protocols:

# HTTP/HTTPS
curl -x http://USER:PASS@gateway.sparkproxy.io:11000 https://www.sparkproxy.io/

# Sticky session, same exit IP across requests
curl -x http://USER:PASS@gateway.sparkproxy.io:11002 https://www.sparkproxy.io/

# SOCKS5
curl --socks5 USER:PASS@gateway.sparkproxy.io:13000 https://www.sparkproxy.io/

Speed caps run 25 Mbps on Starter, 50 on Core, 100 on Boost and 150 on Plus, with higher tiers above that. Those are ceilings rather than guaranteed rates, and they apply to a connection that is not metered by the gigabyte.

If blocking is the problem rather than the IP class, the Scraping API handles proxy selection, retries and rendering behind one request:

curl -G "https://scrape.sparkproxy.io/api/v1" \
  -H "X-API-Key: YOUR_API_KEY" \
  --data-urlencode "url=https://www.sparkproxy.io/pricing" \
  --data-urlencode "country_code=US" \
  --data-urlencode "render_js=true"

It starts with 1,000 free credits and no card, so you can measure it against your mobile quote in an afternoon. Plain fetches cost 1 credit, JavaScript rendering 5, screenshots and PDFs 10, and paid tiers begin at $49 for 250,000 credits a month with 50 concurrent requests. Price that against a per-gigabyte mobile bill for the same job before signing anything.