High-Value
Authenticated
Actions
Automated browser sessions that act on behalf of real end users. The bar is not "works eventually", it's works immediately, because there's a user waiting and the product experience collapses when an agent fails mid-flow.
Modern Anti-Bot Is
Statistical, Multi-Surface,
Continuous
A browser fingerprint is not one field. It is a set of device signals spanning hardware, OS, browser, and configuration. Fingerprinting is collected through HTTP headers and public browser APIs, commonly described as stateless because it does not require storing an identifier in the browser.
The Observable Surface Keeps Expanding
Modern browsers have evolved into feature-rich platforms, Canvas, WebGL, Web Audio, WebRTC, and more, each introducing new, measurable surfaces. Fingerprinting "cannot be fixed with a simple patch" because it's rooted in the core client/server exchange model.
Uniqueness Is Common; Correlation Is The Point
Large-scale studies show high uniqueness rates. In the Panopticlick study, 83.6% of collected fingerprints were unique.
"Agent identity" is not anonymous by default. Anti-bot systems expect coherence and punish divergence.
Why "Randomizing Properties"
Is A Trap
Many teams try to avoid detection by randomly changing a few fingerprint values. This commonly increases risk because it creates contradictions between linked attributes.
The Paradox of Fingerprintable Privacy Enhancing Technologies
Research describes how spoofing tools often forget to update related fields, creating mismatches that are stronger signals of automation than consistent but "wrong" values.
For User Agents, this is fatal. Anti-bot systems do not need to "prove you are a bot." They only need to classify your session as statistically abnormal.
Fingerprint Evolution Study
Fingerprints can be correlated across time, freezing an identity indefinitely becomes an outlier.
Behavioral Biometrics Scale
Keystroke dynamics captured without permissions; deep learning approaches authenticate at scale.
Commercial Deployment
Coherence First.
Continuity Second.
Behavior Third.
A User Agent session is only valuable if it completes successfully, end-to-end, without retries. We own three layers of risk to make that operational reality.
Device Coherence
Your fingerprint must be internally consistent across all 200+ observable surfaces. Not "plausible in isolation", coherent when correlated.
Identity Continuity
Your "device" must persist plausibly over time. Same fingerprint returning to build trust, not a new identity per run.
Behavioral Plausibility
Your interaction patterns must withstand scrutiny, mouse movements, keystroke dynamics, session timing, absence of artifacts.
Cohesive Fingerprints
Resolved Before Launch
Undetect's fingerprint resolver builds full device profiles from minimal hints and resolves the remaining properties into a cohesive match before the browser launches.
Fingerprinting collection is fast and largely permissionless. High-scrutiny login surfaces measure immediately.
A profile that looks plausible in isolation, but breaks when correlated across surfaces, the pattern that kills most "stealth" stacks.
"Sticky" Identities
With Controlled Persistence
For User Agents, persistence is not optional. Many workflows require the same "device" to return repeatedly, banking logins that build trust, healthcare portals that enforce device consistency, account-based flows where new identities increase friction.
Identity-Bound Fingerprints
A fingerprint + its associated session state treated as a single unit. Not "reuse this JSON", an operational identity primitive with managed lifecycle.
Session Sync (S3-Compatible)
Back up and restore identity state to S3-compatible object storage. Persistence is granular: explicitly control what is retained from the browser userDataDir.
Controlled Evolution
Fingerprints change as browsers change. Undetect maintains continuity while allowing controlled, plausible evolution, so your identity stays coherent as the platform changes, not frozen into an outlier.
Self-Hosted By Design.
Engineering Playbooks Included.
User Agent workflows often touch PII, regulated data, or sensitive user actions. Undetect ships as a containerized runtime deployed inside your infrastructure. We do not host your browser fleet. We do not receive your session data.
State-Machine Flow Design
Conditional authentication paths that handle real-world complexity
Deterministic Retries
Bounded risk strategies, not looped brute force
Session Lifecycle Management
Capture, restore, re-auth, rotation rules
Observability Patterns
Explain failures instead of masking them
Because User Agents are our core focus, these playbooks are part of the product outcome, not an afterthought.
Validate First-Attempt Success
On Your Hardest Target
We validate User Agents the only way that matters: against your hardest target, under your constraints, with repeatability. Bring the flow that fails today. We prove first-attempt success, then scale.