Amanda Galvao
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Reusable ID
Turning identity verification into a reusable trust layer
Most identity systems require users to verify themselves repeatedly. This project explored how identity could be verified once and securely reused across services, reducing friction for users and lowering verification costs for the business.
Impact:
4x faster user journey | 2/3 cost-per-check reduction (returning users)
Company
OneID®
Role
UX/UI Designer
Timeline
Nov '24 - Mar '25
The Problem
1
User Friction
Returning users were forced to repeat the same verification process they had already completed. This added unnecessary steps and slowed down the experience.
2
Competitive disadvantage
Many competitors allowed a longer first-time verification but offered near-instant authentication for returning users by reusing verified identity data.
3
High operational cost
Because every verification triggered a new identity check, OneID incurred a cost each time a user authenticated, making the model expensive at scale.
This meant the current model was both inefficient for users and expensive for the business.
The Opportunity
Instead of focusing on faster verification, we reframed the challenge.
The question became:
"How can we verify users quickly?"
to
"How can we verify users once and reuse that trust securely?"
This opened the opportunity to design a Reusable ID system, allowing users to authenticate instantly after completing their first identity verification.
Potential benefits included:
Reduce friction for users during repeat verifications.
Lower costs by avoiding repeated data-source lookups.
Increase product stickiness and encourage return usage.
Support revenue growth through better unit economics.
Understanding the System
Placeholder image:
Systematic diagram
To make reusable identity possible, the system needed to support three key stages:
Initial identity verification
A secure identity check confirming the user’s identity.Trusted identity storage
Securely storing proof that the user had completed verification.Fast returning authentication
Allowing users to authenticate using previously verified identity data.
Designing this system required balancing speed, security, and transparency.
Cross-Industry Inspiration
While exploring solutions, we looked beyond the digital identity space.
Most identity verification providers rely on long onboarding flows and dedicated mobile apps to store and manage credentials. While secure, these approaches introduce significant friction.
We examined how other industries solve a similar trust challenge: allowing users to reuse sensitive information securely across multiple services.
Payment platforms such as Shop Pay and PayPal offer a compelling alternative.
Shop Pay
Shop Pay integrates directly into the checkout flow, allowing users to create an account and store payment details with almost no interruption to the purchase journey. The experience is intentionally low-profile: authentication appears only when necessary, and returning users can complete transactions with minimal effort.
PayPal
PayPal, while more branded, follows a similar principle. It allows users to authenticate quickly and pay without repeatedly sharing bank or card details with individual merchants.
In both cases, the service acts as a trusted intermediary, enabling users to reuse sensitive data while keeping it protected.
In both cases, the service acts as a trusted intermediary, enabling users to reuse sensitive data while keeping it protected.
This revealed a powerful interaction model:
Trusted credentials should work as a lightweight layer within existing journeys, rather than requiring a separate destination or app.
First time experience:
Identity Industry Today
User
service
app download
app onboarding
verification
share details
service
Payment (e.g. ShopPay)
User
checkout
enter details
save & share details
payment completed
Reusable ID (OneID vision)
User
service
verification
save & share details
service (completed)
Design Principles
If payment credentials can be reused seamlessly across the web, the same approach could potentially apply to KYC, age and identity verification.
This reframed the challenge from designing a faster identity check to designing a reusable trust layer for digital identity.
Verify once
Users should only verify a scope (e.g. name) when necessary, without the need to download an app or onboard to service.
Speed for returning users
Authentication for returning users should take seconds and not rely on passwords or memory.
Maintain trust
Returning users should clearly understand what data is being shared with which business.
Authentication
For both user experience and security, we decided to proceed with passkeys for authentication. At this stage, it was still something new but rapidly expanding.
We considered magic links as an alternative for passkey, but in tight dev resourcing, we included passkey only in our first MVP study, accepting that coverage wasn't universal yet.
Edge Cases & Recovery
1. Passkey missing or unavailable
We cannot login user > Full identity verification with any provider > Create new passkey
In this case, we can't connect the user to an account, so we can't suggest them a provider. The user re-verifies themselves as a first time user, and create a new passkey.
If the user selects a different provider, this will result in a new account. This is an issue we accepted to have at a MVP stage since we hadn't validated passkey as authenticator yet.
2. User authenticated but encryption key unavailable
User login > No encryption key found to retrieve their data > Re-verify subject identifier with primary ID provider (at this stage, a bank)
Constraints and Trade-Offs
1
Security requirements
Strict security standards. Putting users' personal and bank details in risk was never an option.
2
Technical constraints
Coordination between authentication systems, identity storage, and verification services.
MVP Scope
To validate the concept quickly, we prioritised the core reusable authentication flow while postponing advanced recovery scenarios.
These trade-offs allowed the team to ship a lean MVP and learn from real usage.
Iteration Strategy
The initial release focused on validating the value of reusable identity.
1
Authentication method validation
We validated that passkey is supported in 84% journeys.
2
Multi-providers coordination
Next, we will study data re-verification process and how to handle multi-data sources vs different compliance requirements.
3
Recovery improvement
With more providers enabled, account recovery will have to rely less in an provider and more in data match.
Impact
Measurable Outcomes
4x
Faster than verifying via a bank
1/3
Cheaper cost-per-check when re-using data
Lessons Learned
Trust is critical in authentication systems
Users must clearly understand when identity data is reused.
Speed drives perceived product quality
Reducing authentication time significantly improved the overall experience.
System design matters as much as UI design
The biggest improvements came from redesigning the authentication model rather than individual screens.
Get in touch
a.galvao@outlook.com
linkedin.com/in/amanda-galv/
@2026 London