200apps · how we work · volume iv of v

● How We Build

From a story ready to pull to a live feature. How meaning survives the code, the pipeline, the review, and the release — without being substituted by what the system happens to do.

Read the opening →

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Part One — The Pull

The Product Owner's walkthrough. What the developer reads. When to ask vs when to decide.

• The Pull — the walkthrough, five artifacts, the line on ambiguity
• When the chain arrives broken — name the gap, record it, decide

Part Two — Domain Language and Composition

Domain language as chain attribute. Ubiquitous language, bounded contexts, component composition, DX.

• Domain Language and Composition — the code speaks the brief
• Bounded contexts and component composition
• Service composition and DX — request-response vs event-driven

Part Three — Design Execution

Full-fidelity, content design, handoff annotations, design system updates, UX review.

• Design Execution — full fidelity, content design
• Handoff annotations and the living prototype

Part Four — The Pipeline

Three environments. Trunk-based. Conventional commits. Seven-stage chain of catches. Migration discipline. Hotfix path.

• The Pipeline — three environments, trunk-based
• Commit discipline and the chain of catches — seven stages
• Migration discipline — four rules
• The hotfix path — when rules are broken explicitly

Part Five — Testing as Chain Verification

Unit, contract, integration, visual, QA craft, accessibility, analytics, signals, SLOs.

• Testing as Chain Verification — unit tests as executable specs
• Visual regression, QA craft, accessibility
• Product analytics — the prediction's measurement instrument
• Signals (leading and lagging)
• System signals, SLIs and SLOs

Part Six — The Review

Three confirmations — PO, QA, Designer — each checking a different dimension. Code review as architecture review.

• The Review — three confirmations, three dimensions
• Code review as chain verification — the trace question

Part Seven — Feature Flags

When to use them and when not. Five-step lifecycle. Gradual rollout.

• Feature Flags — when and when not, the lifecycle
• Gradual rollout and flag setup

Part Eight — The Release

Runbooks rehearsed. Release gate (every item, no exceptions). Four-level rollback. Release brief, CS handoff.

• The Release — runbooks and four-level rollback
• The release gate — full checklist
• The release moment, release brief, CS handoff

Closing

• The Bridge → continues into Volume V

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Supplementary

Pre-restructure corpus pages. Kept while their content is absorbed into the source-aligned pages above.

Domain Language in Code · Trunk-Based Development · The CI/CD Pipeline · Testing Layers · Release Gate · Gradual Rollout · Runbooks & Rollback · Observability