Keeping a bank's markets and lending desks running, then planning their move

Context

Two desks at a Nordic retail and corporate bank. Markets and Treasury, where transactions are processed and settled. Lending, where loans are originated and serviced. Both are systems the business does not get to pause: a stoppage is not a degraded experience, it is transactions that did not clear and loans that did not fund.

The challenge

The work had to hold two things at once that usually pull against each other. The platforms had to run, which rewards changing nothing. And the departments needed new capability shipped into them, which means changing something inside the blast radius of a system nobody is allowed to break. Then a third: leadership wanted a view on moving the whole thing to AWS, which required understanding the estate well enough to say honestly what could move, what could not, and in what order.

My role

Application development analyst on the account. Ran support and incident response across both desks, built and shipped new features into the Markets and Treasury department, and produced the assessment and wave planning for the AWS migration.

Approach

1. 01

   Held availability on both desks — watching for the failures that would have stopped processing, and clearing the ones that arrived

2. 02

   Learned the transaction and loan-processing paths well enough to change them safely, then shipped new features into Markets and Treasury

3. 03

   Mapped the estate for migration: what each component actually depended on, rather than what the documentation said it did

4. 04

   Sequenced the move into waves, ordered by risk to processing rather than by ease of lift

Process

Outcome

• Both desks held their processing windows across three years of support and feature work
• New capability delivered into Markets and Treasury without a change to the availability position
• A migration plan grounded in the real estate, with the order of moves argued from risk