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ADR Example: Strangler-style monolith extraction (Y-Statement format)

Example ADR for decomposing a live monolith without a big-bang: strangler patterns, who owns the write path, and what is explicitly out of scope. The body below is the same decision rendered in the format you choose—use the toggle to compare how each template surfaces risks and follow-ups.

When this type of decision shows up

  • You are peeling off read-heavy or integration edges before touching the core write model.
  • You need a single-writer rule per aggregate while multiple services still touch a shared database during transition.
  • A prior “split the repo” attempt failed; you are encoding a different cutover and rollback story.

Format

Preview

Y-Statement (structured decision record)

Sentence

In the context of the order monolith and 2026 decomposition program, facing coupled deploys and unclear data ownership on extraction, we have decided for a strangler-style incremental extraction with shared DB in transition and explicit per-service ownership in order to smaller release blast radius and clearer contracts without repeating the 2024 big-bang, accepting that we run parallel deployment models and must police shared-table use until write paths split for real.

Fields (same content, for reviews)

  • Context: the order monolith and 2026 decomposition program
  • Concern: coupled deploys and unclear data ownership on extraction
  • Stance / subject: for / a strangler-style incremental extraction with shared DB in transition and explicit per-service ownership
  • Intended outcome: smaller release blast radius and clearer contracts without repeating the 2024 big-bang
  • Deliberate tradeoff: we run parallel deployment models and must police shared-table use until write paths split for real