Build vs Buy · Build vs Buy · Easy · 20-30 min

Banking App — License the Core or Build It

Banking App — License the Core or Build It is an easy Build vs Buy build vs buy case interview that runs 20-30 min. A retail bank needs a new mobile app. A strong answer works through 5 phases: Clarify what differentiates the bank's app vs what is table-stakes plumbing; Compare full build vs license-core-plus-build-layer on time, cost, and differentiation; Weigh time-to-market pressure from the competitor against long-term flexibility; Address integration with legacy core banking and data ownership; Recommend an approach with the trade-offs named.

Last updated 2026-09-05

The brief

A retail bank needs a new mobile app. It can license a white-label banking app platform (fast, proven, but generic) and build only its personalization and loyalty features on top, or build the whole thing in-house for full control. Time-to-market matters — a competitor just launched. You recommend an approach.

How to approach it

  1. Clarify what differentiates the bank's app vs what is table-stakes plumbing
  2. Compare full build vs license-core-plus-build-layer on time, cost, and differentiation
  3. Weigh time-to-market pressure from the competitor against long-term flexibility
  4. Address integration with legacy core banking and data ownership
  5. Recommend an approach with the trade-offs named

What a strong answer does

  • Lands on license the commodity core, build the differentiating personalization/loyalty layer
  • Treats time-to-market as a real strategic cost given the competitor
  • Separates table-stakes features from genuine differentiation
  • Checks integration with legacy core banking systems
  • Names the lock-in trade-off of the white-label platform

Red flags interviewers score down

  • Recommends building everything from scratch despite time pressure
  • Ignores what actually differentiates the app for customers
  • Overlooks integration with the existing core banking stack
  • No view on vendor lock-in

Cases are written in each firm's style, written and reviewed by working consultants; they are not the firms' own published cases.

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