Biometrics are having a moment. Tap your face. Speak a passphrase. Touch your phone. Done. For e-commerce leaders, that sounds like the best of both worlds: less fraud, less friction, more conversions. But there’s a catch: the law treats biometric data like plutonium. It’s powerful, sensitive, and heavily regulated. If you’re planning a biometric checkout, you need a clear-eyed view of the legal risk, where those risks actually come from, and the simple moves that keep you out of trouble.
Let’s cut to the chase: most of the legal pain in this space comes down to when you store, share, or monetize biometric data yourself. If you can design around that, you can reduce both risk and cost—while still getting the conversion lift you want.
First, what counts as a biometric payment?
There are two very different patterns hiding under the same buzzword:
Pattern A: On-device biometrics via platform wallets or passkeys. Think Apple Pay with Face ID, Google Pay with fingerprint, or WebAuthn/FIDO2 passkeys. The biometric data lives and stays on the user’s device. The merchant never sees a face image, a voice print, or a template. You just get a cryptographic yes/no that the user authenticated.
Pattern B: Server-side biometrics. You (or a vendor you hire) capture and store biometric identifiers—face templates, voice prints, palm/vein templates, behavioral profiles—and use them to authenticate users or approve payments. This is where the legal risk skyrockets.
Every choice you make should push you toward Pattern A. It satisfies strong authentication requirements, reduces fraud, and crucially, keeps you away from owning a biometric gold mine you don’t actually want.
The legal landscape (no fluff)
Several laws directly target biometric data. Others hit you indirectly through privacy, consumer protection, or payments rules. The big ones to know:
- GDPR (EU/UK). Treats biometric data used to uniquely identify a person as a special category. That means explicit consent or another narrow exception, a lawful basis under Article 6, a data protection impact assessment, strict minimization, purpose limitation, and heavy penalties for violations. Cross-border transfers require mechanisms like SCCs and a transfer impact assessment.
- PSD2 Strong Customer Authentication (EU/UK). Biometrics can be one of the allowed factors for SCA. You don’t need to collect biometrics yourself to comply; platform wallets and passkeys do the job.
- Illinois BIPA (US). The strictest biometric law in the U.S. Requires written notice, written informed consent, a publicly available retention/destruction policy, strict limits on disclosure, and a ban on profiting from biometric data. Private lawsuits with statutory damages have driven massive class actions. Read the law here: Biometric Information Privacy Act.
- Texas and Washington biometric statutes. Similar themes (notice, consent, limits) but mostly enforced by state AGs, not private plaintiffs.
- New York City Biometric Identifier Law. If you collect biometrics in physical commercial spaces, you need signage and can’t sell the data. Some e-commerce flows touch stores or omnichannel programs—worth noting.
- California CPRA/CPPA. Treats biometric information as sensitive personal information. Expect heightened transparency, purpose limitation, and potential limits on use beyond what’s necessary for the service.
- FTC Section 5 (US). The FTC’s 2023 policy statement warns against misuse, overstatement of accuracy, and weak security around biometrics. Translation: deceptive claims, dark patterns for consent, and sloppy security are enforcement magnets. See the statement: FTC Policy Statement on Biometric Information.
One more trend line: the EU AI Act and similar proposals worldwide are turning up the heat on remote biometric identification. Payments authentication won’t always be in the crosshairs, but the expectation for transparency, risk assessment, and human-centric design is rising fast.
Where teams get burned
Consent that isn’t really consent
Under GDPR, you need explicit consent if you’re using biometrics to uniquely identify someone. Under BIPA, you need written informed consent with very specific disclosures. In practice, the failures look like this: burying it in a 40-page privacy policy, pre-checking a box, or not telling people how long you’re keeping their template. That’s how class actions start.
Retention and purpose creep
Biometric data should be kept only as long as needed and then deleted. BIPA even requires a public retention and destruction schedule. Teams get in trouble when they keep templates indefinitely, repurpose them for personalization or analytics, or keep “forensics” liveness videos in cold storage forever. If you can’t articulate—and document—why you need it and for how long, don’t keep it.
Security that assumes biometrics are passwords
They’re not. If a password leaks, users change it. If a face template or a voice print leaks, it’s permanent. Regulators know this. Expect scrutiny of encryption at rest and in transit, template protection, key management, access controls, liveness detection, and incident response. Also, avoid storing raw images or audio; store templates, and only if you must.
Cross-border transfers without guardrails
Shipping biometric templates to a global vendor’s cloud can trigger GDPR transfer rules. You’ll need the right transfer mechanism and a documented risk assessment. Many companies forget this step because “it’s just auth.” That’s an expensive mistake.
Children, age, and edge cases
Under COPPA, collecting biometrics from kids under 13 requires verifiable parental consent. That includes face images. If you sell youth products or run family accounts, build an age-aware flow and robust parental consent—or avoid biometrics entirely for those users.
Bias, accessibility, and fairness
False rejects aren’t just a conversion problem. If certain demographics fail biometric verification more often, you can create disparate impacts and draw scrutiny. Add ADA/accessibility risk if you don’t provide a workable alternative for people who can’t or won’t use biometrics (injury, disability, religious attire, damaged fingerprints, and so on).
Vendor roulette
Most biometric stacks are vendor-heavy. If your vendor stores templates, trains models with your users’ data, or reuses data across clients, you own the fallout when things go wrong. You need processor agreements, audit rights, security obligations, deletion SLAs, and indemnities that actually mean something. If the vendor won’t sign a BIPA-compliant addendum for U.S. users, that’s a red flag.
Dark patterns and pressure tactics
“Tap Accept to finish checkout” isn’t consent when the only choice is accept. Regulators are itching to go after coercive screens, manipulative copy, and sneaky default settings that funnel users into biometrics. Keep the copy plain, optional, and reversible.
The BIPA wildcard
Why do lawyers get twitchy about biometrics? Because BIPA allows private lawsuits with statutory damages—often calculated per person, per scan. That’s why you see nine-figure settlements in the news. Even if you win, the legal fees and discovery burden are brutal.
The safer lane: use passkeys and platform wallets
There’s a reason the industry is moving to passkeys and platform wallets. With passkeys (FIDO2/WebAuthn), the biometric stays on the device. You get strong, phishing-resistant authentication with almost no regulatory blast radius. Learn more here: FIDO Alliance on passkeys.
Similarly, Apple Pay and Google Pay satisfy SCA and boost conversion on mobile without you ever touching a biometric. In other words: you get the conversion lift without inheriting the liability that comes from storing body-based identifiers.
If you still plan to collect or store biometrics, do this
- Run a privacy and legal design workshop early. Decide if you truly need server-side biometrics. If you can’t articulate why device-based options don’t solve your use case, hit pause.
- Map the data. Document exactly what you collect (images, templates, liveness data, behavioral signals), where it flows, who touches it, and where it’s stored. Create or update your records of processing.
- Pick the right legal bases. For GDPR, you’ll likely need explicit consent and a lawful basis for processing. For BIPA, prepare a written notice and consent flow that meets the statute’s elements.
- Write a public retention and destruction policy. Keep it short. State what you collect, why, how long you keep it, and how you delete it. Set default retention to the minimum that still works.
- Build a real consent flow. Plain language. No pre-checked boxes. Separate from general terms. Let users opt out and still complete checkout with an alternative method.
- Engineer for minimization. Use templates, not raw images. Avoid storing liveness videos. Don’t repurpose data for marketing or personalization. Encrypt everywhere and lock down access.
- Offer equal alternatives. Provide passkeys, OTPs, or other non-biometric options. Make them easy to find and fast to use. Document why your alternatives are equivalent.
- Harden vendor contracts. Get a DPA with processor-only terms, location of processing, no secondary use, deletion on demand, breach notice timelines, BIPA addendum for U.S. users, and meaningful indemnities.
- Do a DPIA and security review. Include attack simulations, bias/accuracy testing across demographics, and an incident response run-through. Record the findings and fixes.
- Handle cross-border transfers properly. If any biometric data leaves the EU/UK, implement SCCs and a transfer impact assessment. Don’t assume your vendor already did it for you.
- Plan for data subject requests. You’ll get requests to access or delete biometric data. Make sure your systems can find and erase templates quickly and prove it happened.
- Train your team and update your comms. Customer support needs a playbook for biometric questions and objections. Marketing needs copy that doesn’t overpromise accuracy or safety.
Real-world patterns: what’s smart vs. what’s risky
Smart: Enable passkeys on web and app, default to Apple Pay/Google Pay on mobile, and offer SMS/email OTP as a fallback. Market it as passwordless checkout. You never touch a biometric. You still get SCA and conversion wins.
Risky: Build your own face-ID checkout where users enroll by taking a selfie, you store a face template, and your vendor keeps liveness detection videos “for quality purposes.” You’ll need GDPR explicit consent, BIPA-compliant notice and consent in Illinois, a public retention schedule, heavy security, and bulletproof vendor controls. You’re also on the hook for deletion, cross-border transfers, and any bias problems that appear later.
Somewhere in the middle: Use a vendor that claims “template-only, no images stored,” with on-device matching for a subset of platforms. Better, but audit the claims and put them in the contract. If your logs or analytics accidentally keep face images, you’re right back in high-risk territory.
Common speed bumps (and how to clear them)
Internal pushback: “But biometrics convert better.” True in some contexts—but passkeys and wallets are catching up fast, and you avoid legal drag. Run an A/B test. Let the data guide the decision.
UX concerns: “Too many choices.” Present the best option first (passkeys or wallets), with a clear link to alternatives. Keep it simple and accessible.
Legal ambiguity: “Do we really need explicit consent?” If you’re storing templates or doing server-side matching for identification, assume yes in the EU and Illinois, and build the consent flow once. It’s cheaper than litigating it later.
What to ask vendors before you sign
- Do you store raw images or only templates? For how long? Where?
- Can you guarantee no secondary use, training, or sale of my users’ biometric data?
- What’s your deletion SLA after we or the user request it?
- How do you handle BIPA, Texas, and Washington compliance in the U.S., and GDPR in the EU/UK?
- What’s your liveness detection false reject rate across demographics? Share the latest independent test results.
- Can we audit your controls? What third-party certifications do you have?
- Describe your breach notification timeline and indemnity. Is it capped? On what?
A word on payments rules
Teams sometimes reach for biometrics to “meet SCA.” Remember: PSD2 SCA allows inherence factors, but it doesn’t require you to collect biometrics yourself. Platform wallets and passkeys satisfy SCA without you touching sensitive data. For the EU specifics, start here: EBA SCA resources.
Bottom line
Biometric payments can reduce fraud and unlock a faster checkout. But the legal risks spike the moment you start collecting or storing the biometric data yourself. If you stay in the safer lane—passkeys, Apple Pay/Google Pay, and strict minimization—you’ll get most of the upside with a fraction of the legal exposure. If you decide you truly need server-side biometrics, build it like a regulator is looking over your shoulder: explicit consent, short retention, strong security, fair alternatives, audited vendors, and documentation for days.
One last practical tip: run your plan past privacy counsel before you write a line of code. It’s cheaper than reengineering a checkout flow—or defending a class action—after launch.
This article is for general information and not legal advice.
