Bank A × Bank B — Cross-bank migration
Customer migration - seamless banking transition
Following Bank B’s acquisition of Bank A, 5 million retail and business customers needed to be migrated safely from Bank A’s digital platform to Bank B’s - with no disruption to account access and no loss of trust. I led the UX design of the migration journey, including the OIDC handoff flow, maintenance states, and special use case journeys.
MY ROLE
Lead UX / Product designer
scale
5 million customers
platform
iOS, Android,
online bankng
status
Defined for delivery -
live Q2 2027
Impact
Impact at a glance
5m
Customers being migrated
2 banks
One seamless customer journey
4
Distinct customer states designed for
Q2 2027
Target go-live
01
My role
Design leadership across non-standard customer journeys
Design lead
Led UX design for Bank A's side - login entry points, redirect screens, maintenance banners, and transition states up to the OIDC handoff
Special use cases
Designed bespoke journeys for Power of Attorney accounts, dual-banked customers, and read-only business users
Cross-org collaboration
Weekly design sessions with Bank B's team via a shared Figma file, aligning both sides of the flow
AI as a thinking partner
Used AI to map flow logic, pressure-test edge cases, and make sense of the OIDC authentication architecture - translating technical complexity into UX decisions
02
Problem
How do you move 5 million people between banks without them noticing?
If these scenarios were pushed into exceptions or support processes, the product would feel unreliable exactly when customers needed clarity most. The challenge was to make complex access rules visible without making the mainstream journey feel heavy.
“Early usability testing showed customers didn’t trust the handoff. Being redirected away from your bank during login reads as a scam, not a feature.”
Reframe
From “build an OIDC redirect flow” → “design a handoff that 5 million customers trust enough to complete”
03
The design challenge
Trust at the moment of maximum anxiety
Problem
Trust collapse at the handoff
Usability testing showed customers interpreted the OIDC redirect as suspicious - several participants abandoned the flow entirely, assuming their account had been compromised.
Decision
Transparency over efficiency
We explained what was happening, why, and what to expect next before any redirect occurred - making the transition visible and legible rather than technically seamless. This added a step but eliminated the anxiety causing abandonment.
Problem
Four distinct customer states
The migration API returns four possible outcomes per customer. Each required a distinct journey, all needing to feel consistent despite serving very different situations.
Decision
State-based journey system
We built a consistent component system - banners, redirect screens, confirmation states - configurable per customer state, keeping the experience coherent and simplifying engineering implementation.
04
Special use cases
Three segments that couldn’t follow the standard flow
Power of Attorney
Impossible to distinguish PoA from donor digitally - directed to postal credentials with a clear explanatory screen and fallback guidance.
Dual-banked customers
Customers with accounts at both banks redirected to Bank B login with contextual messaging to avoid credential confusion.
Read-only business users
Bank B has no read-only functionality - redirected to web OIDC flow with clear explanation of what changes post-migration.
05
Cross-org collaboration
Creating one shared product language across two organisations
Two banks, two design teams, two sets of legal and compliance requirements - and one customer experience that needed to feel seamless. Weekly cross-bank design sessions and a shared Figma file kept the seam between both sides of the journey as invisible as possible.
Bank A design team
Login entry points, migration banners, and redirect screens up to the OIDC handoff point
Bank B design team
First-time login setup and onboarding experience post-handoff
06
Success criteria
What good looks like when it goes live
We defined success around confidence, explainability, and operational readiness rather than visual completion alone.
High onboarding success rate
% of migrated customers completing first login on Bank B’s platform, tracked across retail and business
Low drop-off at OIDC handoff
The point usability testing flagged as highest risk - monitored per migration wave
Vulnerable customer journeys protected
PoA and under-19 onboarding tracked separately, in line with Consumer Duty requirements
Sustained activity post-migration
% of customers logging in within 7 and 30 days, confirming substantial engagement
What makes this different
No launch metrics yet - but the complexity is the story. Designing a trusted handoff for 5 million customers across two banks, two design systems, and four distinct customer states is a different kind of problem to a single product journey.