Edge BFF: when it pays off (and when it doesn’t)
A straight take on Next.js edge routes and regional compute - latency wins, sharp edges with Node-only libs, and how we decide per project.
“Move everything to the edge” sells conferences. In client work we pick edge when it measurable affects UX - not by default.
When edge shines
- Read-heavy BFF shaping responses for the browser: auth checks, fan-out to fast upstreams, HTML tweaks - especially when users are globally distributed.
- JWT/session gates close to the user with minimal cold-start surprises on stable routes.
When we stay on Node (or containers)
- Heavy
nodemailer, PDF generation, long CPU work, or libraries that assume full Node APIs. - Workloads needing large payloads, streaming quirks, or vendor SDKs that aren’t edge-safe yet.
Rule of thumb
Prototype on Node until profiling proves edge removes real latency from your p95. Swap critical paths - don’t cargo-cult the runtime.