Know Your Device (KYD)
Definition. Know Your Device is Noxtica’s browser-based device-intelligence concept. It turns a browser assessment into a site-scoped fingerprint identifier and risk context that can be used across permitted sessions and backend workflows.
The problem it solves is continuity without pretending to know a person. Account and fraud teams often need to ask whether a browser/device context has been seen before, whether its characteristics are internally consistent, and what risk evidence accompanied the assessment. KYD provides those inputs without making the final decision.
A device identifier is not a verified person, account owner, or guaranteed physical device. It is a handle for the assessed context under the current site, browser, storage, and collection conditions.
When it applies
KYD can inform:
- new-device and returning-device review;
- signup and promotion-abuse controls;
- login, account recovery, and step-up decisions;
- transaction review alongside account and payment context; and
- support investigations into why a session received friction.
Use KYD where your team has a defined decision and fallback. Do not collect an identifier merely because it is available.
How customers use it
- Add the browser collector with a provisioned Site Key.
- Call
checkOnce()or use automatic collection to receive the current browser result. - Store
fingerprintIdwith the relevant session or account when your retention and access design permits it. - Read the current risk context in the operator console or retrieve device data from the Server API with a scoped server key.
- Combine device history and risk fields with your own account, route, and transaction context.
- Apply the action in your backend or through separately provisioned policy controls.
See Getting started for collection and Backend integration for the supported lookup workflow.
How Noxtica does it
Browser Intelligence gathers multiple categories of browser and edge context. KYD presents the resulting customer-facing artifacts:
- Fingerprint identifier — a site-scoped handle returned as
fingerprintId. - Device history fields — supported first-seen, last-submitted, and last-seen timestamps available through device lookup.
- Risk score and level — a 0–100 score and named tier for policy segmentation.
- Confidence — context for how strongly to rely on the assessment.
- Flags or reasons — contributing conditions an operator can investigate.
The protected browser runtime is designed to raise the cost of result manipulation and replay. It does not make a browser impossible to inspect, guarantee continuity, or establish a hardware or legal identity.
Outputs and decisions
| Output | Customer use |
|---|---|
fingerprintId | Associate permitted observations with a session or account workflow |
| First/last-seen context | Distinguish newly observed from previously observed context |
score and riskLevel | Select a route-specific review or step-up band |
confidence | Decide whether the available evidence supports a strong action |
flags | Explain and investigate what contributed to risk |
For example, a newly observed identifier with elevated risk and limited confidence may warrant reversible step-up rather than a permanent denial. A familiar identifier still passes normal authentication and authorization; familiarity is not approval.
Supported limitations
- Clearing storage, private browsing, browser or device changes, privacy tools, blocked scripts, and collection settings can affect continuity or available evidence.
- A fingerprint can represent a browser profile rather than a single immutable physical device.
- Cross-site tracking is not the customer contract; use the identifier only within the provisioned tenant and site context.
- Cached assessments can be older than the current visit. Use the configured refresh interval and timestamps when freshness matters.
- Native iOS or Android attestation is separate from browser KYD and requires its own supported integration and tenant eligibility.
- Risk output complements but does not replace identity verification, authentication, authorization, or transaction controls.
Where it fits
KYD is the device part of the Intelligence pillar. It receives evidence from Browser Intelligence, complements eligible Know Your Agent context, and supplies inputs to Browser Security or customer-owned backend policy.
Read deeper
- Getting started — collect the current browser result.
- Backend integration: API Reference — retrieve device risk with a scoped server key.
- Browser runtime — cache, lifecycle events, errors, and collection modes.
- Features: device and browser intelligence — interpret the identifier and its risk context.
- Why calibration, not verdicts — choose policy without treating risk as identity.
- Browser Intelligence — the evidence categories that feed KYD.