Running Undetectable.io Profiles on a Monthly SIM Proxy

Undetectable.io is the antidetect browser we recommend to SimProxies customers, and the two fit together naturally: the browser gives each profile its own device fingerprint, and the SIM gives each profile its own carrier address. The combination only works if you keep the pairs stable, which is exactly what a monthly SIM is for. This guide walks through the setup from a fresh install to a profile that has been living on one SIM for weeks, with the settings that matter and the mistakes that undo them.

What each side is responsible for

The browser controls what a website learns about the device: screen, fonts, canvas, WebGL, time zone, language, and the dozens of smaller signals that make up a fingerprint. The SIM controls what the website learns about the network: a US carrier, a metro, an address shared with ordinary phones. A site compares the two. A profile that claims a Chicago time zone over a Chicago carrier address is coherent; the same profile over a datacenter range in another country is not.

So the rule is one profile, one SIM, for the life of the profile. Undetectable.io makes that easy to enforce because the proxy is a property of the profile, not of the browser.

Setting up the profile

The whole setup takes a few minutes. Have your SimProxies dashboard open in another tab so you can copy the line's details.

1. Install Undetectable.io on Windows or Mac and create an account. The free plan is enough to start and allows a handful of cloud profiles.
2. In your SimProxies dashboard, open the line and copy the host, the HTTP or SOCKS5 port, the username and the password.
3. Create a new profile in Undetectable.io. Choose a mobile or desktop fingerprint depending on what the account expects; both work over a SIM.
4. Open the profile's proxy section, pick HTTP or SOCKS5 to match the port you copied, paste the four values and press the check button. It should report a US carrier and the city of your SIM.
5. Set the profile's time zone and language to the SIM's city: Central time and US English for Chicago or Houston, Eastern for New York, Miami, North Carolina and Boston, Pacific for Los Angeles, Mountain for Phoenix.
6. Save, launch the profile, and load an IP check page before you log in anywhere. Confirm the carrier and the city once more.

Keeping the pair together for the month

Once the profile has logged in through the SIM, leave both alone. Do not open the profile over a different proxy, and do not use the SIM for a second profile that should look like a different person. If you need another identity, rent another SIM. A monthly plan keeps the same SIM in the same modem, so the address history the profile builds stays attached to it from the first login to the last.

Rotation is still available, and it is harmless when used between sessions: the new address is from the same carrier in the same city. Rotating in the middle of a logged-in session is the one thing to avoid, because the site sees the address change while the fingerprint stays put, which is a pattern worth not showing.

Settings that give the game away

The common failures are not about the proxy at all. A profile with the wrong time zone is the most frequent; a page checks the clock against the address and sees two different places. A browser that leaks the real address through WebRTC is the second; Undetectable.io can disable or mask it, so make sure that option is on. Location services and a saved GPS position come third on laptops with a location sensor. Finally, logging in from a personal browser to check something quickly links the account to your real network in one request.

• Time zone and language set to the SIM's city, not your own
• WebRTC masked or disabled in the profile
• No personal browser logins to the same account, ever
• Rotate between sessions, never during one

Scaling to several profiles

Teams usually end up with a short table: profile name, SIM, city, carrier, renewal date. Undetectable.io lets you import proxies in bulk on the larger plans, which saves typing, but the table is still worth keeping so nobody opens a profile on the wrong line. Group profiles by city if the accounts are regional, and keep renewals aligned so the lines do not lapse one by one at awkward hours.

When something does not connect

If the proxy check fails, confirm the port matches the protocol you chose, and that the username and password were pasted without a trailing space. If the check passes but the site shows a captcha on every visit, the profile's fingerprint and the address disagree somewhere; recheck time zone and WebRTC. If the address resolves to a neighboring city, that is a database lag and clears on its own. For anything else, support is on email and Telegram and can see the line's status from our side.

Frequently asked