Can websites detect a datacenter or proxy IP?

Yes, directly. The server sees the address your connection arrives on before a single line of your JavaScript runs, and it can look that address up: which network owns it, whether it belongs to a hosting provider or a home broadband line, and whether it has been abused recently. No browser fingerprint changes that lookup, because the address is a property of the connection, not of the page.

This is the honest boundary of any browser-side stealth. A tool like invisible_playwright makes the browser look like a real person’s, and that is most of what public detection checks read. It does not, and cannot, change the reputation of the IP you route through. Those are two independent layers, and both have to be right.

What the server reads before your page loads

Every request carries a source IP. From that one number the receiving server derives, with no cooperation from you:

The ASN, the autonomous system number, which identifies the network that owns the address block. Hosting and cloud providers have their own ASNs, and they are trivially separable from consumer broadband and mobile carriers.
The address type, datacenter versus residential versus mobile, which public and commercial datasets label directly.
Reputation, meaning whether this address or its neighbours have recently sent traffic that looked automated or abusive. Shared and heavily recycled exits accumulate this quickly.

None of that is a browser property. It is decided at the network layer, the same layer that carries the TLS handshake no in-page test can see. A perfect fingerprint sitting on an address the server already distrusts is a consistent browser on a flagged IP, and the flag wins.

Why the fingerprint cannot reach it

The fingerprint cannot reach the IP because the two are different kinds of value: the fingerprint is data the browser volunteers to the page, and the IP is decided by the network carrying the connection, which the page never touches.

A fingerprint is everything the page can measure about the client from inside the sandbox: the user agent, the GPU string, the canvas and audio hashes, the font list, the screen, the language settings. All of it is data the browser volunteers in response to JavaScript. That is exactly why it is spoofable, and why matching it to a real Windows machine is worth doing.

The IP is the opposite kind of value. It is not something the browser reports; it is where the packets came from. The browser cannot lie about it because the browser is not the one telling the server. The network is. You can change which IP you arrive on by routing through a different proxy, but you cannot make a given IP read as something it is not, and no amount of in-page patching touches it. This is the single most common misunderstanding about stealth: people expect a good fingerprint to cover the address, and the two never meet.

Both layers, independently, with the real API

Because the layers are independent, you supply the IP and the tool supplies the browser. The proxy is passed at launch, and everything downstream is stock Playwright:

from invisible_playwright import InvisiblePlaywright

proxy = {
    "server": "socks5://gate.example.com:1080",
    "username": "user",
    "password": "pass",
}

with InvisiblePlaywright(seed=42, proxy=proxy) as browser:
    page = browser.new_page()
    page.goto("https://example.com/")
    print(page.title())

Two things are happening here, and they are separate. seed=42 fixes the browser half: the same GPU, canvas hash, audio context, fonts and screen every run, so a failure is reproducible. proxy=... fixes the IP half: every request, including DNS, leaves through that exit. The browser object is a real Playwright Browser, so new_page, goto, click and the rest behave exactly as documented upstream.

By default, with no timezone= argument, the browser timezone is derived from the exit IP so the two stories agree. If you want to confirm the exit is what you think it is, read it from inside the browser rather than assuming, and check that WebRTC is not reporting a second address next to the proxy’s.

Choosing the IP half so it does not undo the browser half

The fingerprint work is wasted if the address is one a server distrusts on sight. Two rules follow directly from what the server reads:

Type matters more than count. A residential or mobile exit shares an ASN and an address type with ordinary human traffic; a datacenter exit does not, no matter how many of them you rotate through. Rotation does not change the type.
Freshness matters as much as type. A large share of cheaply available proxies are already public, which means their addresses are already on the lists servers consult, and they were flagged before you ever used them. The distinction between a clean exit and a burned one is not price, it is whether the address is already known. The tradeoffs between exit protocols are covered in SOCKS5 versus HTTP proxies for a browser, and the reputation problem itself in why scraping gets blocked even through a proxy.

Get both halves right and the server sees a genuine Firefox arriving from an address that looks like a person’s. Get the browser right and the IP wrong, and you have built a careful disguise and then signed it at the door.

What this does and does not fix

To be explicit, because overclaiming here is both false and a real risk:

invisible_playwright is designed to look like a real browser driven by a real person, and that is why it passes most fingerprint, TLS and driver-layer checks: those layers read as a genuine Firefox. On its own it does not fix IP reputation, per-account quotas, rate limits, or behaviour and timing. Those are yours to supply: a clean exit for the address, human pacing for the behaviour, sane limits for the account. There is no setting that makes an IP undetectable, because the IP is not something the browser gets to describe.

Conclusion

Can websites detect a datacenter or proxy IP? Yes, directly and early, at a layer no fingerprint reaches. The browser fingerprint and the IP are independent signals, read by different parts of the stack, and a detector that sees a perfect browser on a flagged address believes the address. So match the browser, which is what this tool does, and pair it with an exit whose type and reputation hold up, which is what you bring. Neither half alone is a session; both right is.

Short answers to the questions that lead here

Can a browser fingerprint hide my IP? No. The IP is where the connection comes from, not something the browser reports, so no in-page value or spoof changes it.

Will a residential proxy alone get me through? It fixes the address half. If the browser still looks automated, a clean IP does not save it. Both layers have to be right.

How does a site know my IP is a datacenter? From the ASN and address-type datasets tied to the IP. Hosting networks have their own autonomous system numbers and are labelled as such in public data.

Does rotating IPs help? It helps with rate limits and per-address velocity. It does not change the type: rotating datacenter exits are still datacenter exits.

Can invisible_playwright change my ASN or reputation? No, and nothing on the browser side can. It handles the fingerprint, TLS and driver layers; you supply the exit.

Why do I pass every fingerprint test and still get blocked? Because the suites do not see your address, and a consistent browser on a distrusted IP is still on a distrusted IP.

Sources

RFC 1930, the IETF guidelines that define an Autonomous System as a routing policy unit and specify the ASN that identifies it.
Playwright’s Browser class reference, for what the browser object in the example above exposes once the proxy is wired in.
This project’s default behaviour: the proxy dict passed at launch routes every request and its DNS through the exit, and the browser timezone is derived from that exit unless an explicit zone is set.
The configuration notes on proxy schemes and on why roughly nine in ten cheap proxies are already known before first use.
The testing method page, which lists IP reputation among the things no in-page suite covers.

Written while maintaining invisible_playwright, a Firefox patched at the C++ level driven by stock Playwright. The browser half is what the patch does; the IP half is the one honest thing it cannot do for you.