We standardise on Postgres for new services
Decided 14 Mar 2026 · R. Vance
New services use Postgres unless they have a documented reason not to. Existing MySQL services are not migrated on this basis alone.
The deciding factor was operational familiarity, not a technical benchmark. Both would have worked.
What we considered and rejected
MySQL (status quo, but two dialects to operate), DynamoDB (cheap at scale, but our access patterns are relational), CockroachDB (solves a distribution problem we do not have).
Event bus stays on managed Kafka until 2028
Decided 02 Jun 2026 · L. Ferrero
The self-hosted alternative saves roughly €90k a year and costs approximately 0.4 FTE to operate. At current headcount that trade is not worth making.
Revisit if the team grows past twelve engineers, or if managed pricing rises more than 20%.
Services are named after what they do, not after gods
Decided 19 Jun 2026 · team
billing-api, not hermes. A new joiner should
be able to read an architecture diagram without a glossary.
Who owns the legacy SFTP contract?
Open — blocking raised 28 Aug 2026
The file gateway migration cannot start without an owner for the supplier contract. This is currently blocking one wave 2 workload.
Next step: raised with procurement 05 Sep, no reply yet.
What is the retention policy for cold archive?
Open raised 01 Sep 2026
Legal have not confirmed whether the seven-year rule applies to derived data or only to source records. The answer changes the storage tier and roughly €14k a year.
Should on-call cover the migration window?
Open raised 08 Sep 2026
Undecided. The team is split; no decision is needed before 1 November.
Terms
Reference
- Wave
- A batch of workloads migrated together, sharing a cut-off date.
- Cut-off
- The date after which a wave's workloads must run on the new platform.
- Derived data
- Anything computed from source records — aggregates, indexes, caches. Whether retention applies to it is currently an open question.