Technical Specification (Tech Spec)

Not every feature needs a tech spec — writing unnecessary specs slows delivery. A spec is valuable when: the feature requires significant architectural changes or new infrastructure; multiple engineering teams must coordinate (e.g., platform, data, and product teams); the feature has significant security or compliance implications; there are meaningful implementation approaches with different long-term tradeoffs; or the feature requires new third-party integrations. A good rule of thumb: if the implementation decision requires input from more than two engineers and will last more than 6 months, write a spec. Product Ops maintains a "spec required" decision framework that engineering leads use to decide when to invest in a spec versus moving directly to implementation.

A comprehensive tech spec includes: Background & Motivation (the user problem being solved and why this approach); Proposed Design (system components, data flow diagrams, API contracts, data model changes); Implementation Plan (phased approach, milestones, dependencies); Alternatives Considered (other approaches evaluated and why they were rejected — this is the most valuable intellectual content); Security & Privacy (how the design handles data security, access control, and compliance requirements); Performance Requirements (latency, throughput, and scalability targets); Rollout Plan (feature flag strategy, migration plan for existing data, monitoring approach). Product Ops provides a standard template and hosts a 30-minute spec review ceremony where Engineering, PM, and Design align before implementation begins.

The spec review process must be fast enough not to become a bottleneck. The most effective approach is asynchronous review followed by a synchronous decision meeting. The author shares the draft 48 hours in advance, reviewers leave comments asynchronously, and then a 30-minute session resolves outstanding disagreements. Product Ops schedules and facilitates these sessions and tracks one metric: spec-to-implementation start time. If this consistently exceeds one week, the process is too slow and needs streamlining. After the meeting, Product Ops documents the final decisions and alternatives rejected, creating an Architectural Decision Record (ADR) that future team members can reference to understand why the system works the way it does.