Fintech M&A is a frequent occurrence in the UK tech scene and should be considered an engineering risk. Recent examples highlight how acquisitions can alter product trajectories and create integration challenges. Visa's acquisition of Plaid shifted focus towards enterprise terms, making onboarding more difficult for smaller businesses. TrueLayer's API migration required significant developer effort to adapt to new requirements. GoCardless's acquisition of Nordigen led to a scaled-back free tier, forcing some developers to re-evaluate their technology stack. It is statistically likely that any business relying on third-party payment APIs will encounter changes due to acquisitions or pricing shifts. To mitigate this risk, developers should build a thin abstraction layer around vendor SDKs, insulating their core business logic. Storing a canonical payment state in their own database is crucial for maintaining data integrity during vendor changes. Observing early signals like scaled-back free tiers or slower support can indicate impending platform shifts. Budgeting speculative migration time into roadmaps allows for quicker adaptation to unsolicited changes. Ultimately, acknowledging vendor API business risks and creating architectural distance is essential for resilience.