Multilogin Detection

How to detect Multilogin in 2026

Multilogin helped invent the commercial antidetect category and still sets its vocabulary: browser profiles, two custom engines — Mimic (Chromium-based) and Stealthfox (Firefox-based) — and team workspaces for operating accounts at scale. Sentinel treats each of its sessions as a claim to be a real device, then checks that claim against the engine, the runtime, the network, and the device's track record.

What Multilogin is

Running since the mid-2010s, Multilogin is the longest-established name in the space, and its marketing reflects a professional customer base: subscription tiers priced by profile count, team member seats with shared profile access, cloud-synced profiles, and automation support through Selenium, Puppeteer, and Playwright plus a local API. Maintaining two separate engines is its signature feature — operators pick Mimic when a site expects Chrome and Stealthfox when Firefox draws less attention. It positions all of this, in its own words, as multi-account management.

How Sentinel scores a Multilogin session

Two custom engines mean twice the burden of imitating real browsers perfectly — every claim a profile makes has to agree with how the underlying fork actually behaves. Sentinel's device layer is built to notice exactly that kind of disagreement, and the network and history layers don't care which engine was used at all.

The antidetect flag

Rebuilt engines that override the fingerprint surface are detectable as a category. Sentinel returns device.antidetect and the antidetect_browser reason code when those traits are present — no per-vendor signature list to go stale.

Tampering score (0–1)

device.tampering_score quantifies fingerprint manipulation. A profile claiming a stock Firefox on Windows while the engine underneath behaves like neither pushes the anomaly measure up; above 0.6 reads as a strong antidetect indicator, 0.3–0.6 as soft inconsistency.

Engine/OS coherence checks

The tampering model leans on cross-checks a spoof must win all of: claimed browser version vs real engine behaviour, claimed OS vs platform internals, and spoofed surfaces that must not contradict each other.

Framework-driven profiles

Multilogin's automation integrations are a selling point — and Puppeteer-, Selenium-, or Playwright-driven sessions are what device.automation exists to catch (reason code automation_detected).

Virtualisation

Team operations frequently isolate seats in VMs. device.virtual_machine and device.emulator score the host environment independently of whatever profile is loaded.

Network & history layers

Profiles ride residential proxies or VPNs, which Sentinel's Spur-powered network layer flags on its own. Meanwhile device.times_seen and linked_accounts record reuse — a shared team profile touching many of your accounts trips multi_account.

The honest version: a decade of commercial hardening means well-run Multilogin sessions are genuinely difficult, and no vendor — Sentinel included — catches every one, every time. What layering buys you is that the operator must win the engine check, the automation check, the network check, and the history check simultaneously, on every request. Sentinel hands you each signal plus a 0–100 score; your rules decide the response.

Putting it to work

Add the Sentinel SDK to signup, login, and checkout, then evaluate server-side via /v1/evaluate. The response includes device.antidetect, device.tampering_score, and the network and history fields. The API reference documents every field; the antidetect detection deep-dive explains the method. For the tool-specific breakdown, see Multilogin field notes: what fired and what missed in 2026.

Put Multilogin traffic under a layered lens.
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