Compare build deltas quickly — toggle treemap to a searchable diff table

Frontend teams and build engineers waste hours every week chasing ambiguous bundle treemaps that hint at regressions but don’t tell you which changed files or imports actually caused a size or performance delta. The problem is acute for modern apps using code-splitting, dozens of third-party packages and rapid PR-driven workflows, where a single commit can ripple across many bundles and create noisy visualizations that are hard to triage in the 10–30 minutes available during code review. You could build a small, fast layer that lets users toggle a treemap into a searchable, filterable diff table showing file- and import-level deltas, sortable by bytes, runtime impact, and ownership, with source-map resolution, commit/PR links, CI annotations and optional correlations to runtime performance traces. Delivering this as CI-friendly artifacts and a lightweight browser UI that integrates with webpack/esbuild/rollup and GitHub/GitLab would give developers an actionable list of 5–10 highest-impact deltas instead of a vague visual blob. The timing is favorable: frontend complexity, the shift-left push for PR-level feedback and growing expectations to connect build metrics with runtime observability create clear demand, and the TAM you’ve estimated—roughly $6.0B (2M teams × $3K ACV)—means even modest penetration yields meaningful revenue potential. This idea can stand out by focusing on precision and workflow integration rather than prettier treemaps—source-map-aware diffs, low-noise heuristics and PR-native annotations are defensible differentiators—but the hard parts are real: reliable mapping across build toolchains, avoiding false positives, and getting the first canonical integrations into popular CI and repo hosts. If you can solve those engineering challenges and demonstrate a 2×–5× speedup in triage time for early customers, the product can win a sustainable niche despite medium competition.