02/Architecture
The decisions, mapped to where they live.
A growing reference of the system-design judgment behind the work. Each topic links to the case study where the decision actually shows up, so it stands on a real system rather than a definition. Written deep-dives are in progress; the anchors are the proof in the meantime.
Identity & access
3 topicsOIDC sign-on and identity federation
Deep-diveSigning a user in once and reconciling their identity across products that do not share a database.
Read the decision record
RS256, JWKS, and key rotation
Verifying tokens against rotating public keys without locking everyone out on a stale cache.
Seen in ILM Platform
Multi-tenant authorization
Letting each organization type see only what it owns, with escalation guards on identity hints.
Seen in ILM Platform
Legacy modernization
3 topicsStrangler-fig migration
Replacing a live backend incrementally instead of a big-bang rewrite, with no downtime for users.
Seen in Cascade
Graceful degradation across data sources
Keeping new features working when a legacy database connection is unavailable.
Seen in Cascade
Backward-compatible auth coexistence
Running a new and a legacy auth provider side by side so access never breaks during a cutover.
Seen in ILM Platform
Trust & verifiability
2 topicsTamper-evidence and hash chains
Making a record independently verifiable through content hashing, a hash-chained log, and on-chain anchoring.
Seen in Booppa
Response encryption and key custody
Encrypting sensitive payloads with AES-256-GCM, and being honest about where the keys should live.
Seen in Booppa
AI in production systems
2 topicsData & performance
3 topicsRead-heavy analytics over large schemas
Serving dashboards and KPI rollups from a dedicated read path with HTTP caching, over a 114-model domain.
Seen in ILM Platform
Query consolidation
Replacing dozens of per-category aggregate queries with conditional aggregation pushed into the database.
Seen in ILM Platform
Modeling operational reality relationally
Turning a real-world resolution problem into an indexed relational schema, even on a constrained platform.
Seen in SingPost
In progress
I am writing each of these up as a decision record: the forces, the options, the trade-off, and when to revisit it. The first is published; topics marked Deep-dive link to it. Until the rest land, the case studies carry the detail.