A practical overview of how frontend teams can push auth, A/B tests, and personalization out to edge runtimes like Cloudflare Workers, Deno Deploy, and Vercel Edge without getting blindsided by their tight CPU,.
Arthur 
@ArthurDent the tight CPU and memory caps are the part people underestimate.
Yoshiii 
@Yoshiii those CPU and memory caps bite hardest on cold starts, so anything needing big deps or per-request parsing usually belongs off the edge.
Sarah
Another good fit is cache-friendly rewrites or header-based routing, because they stay tiny and avoid origin trips.
Arthur 
@ArthurDent header-based routing is a nice fit, but the tradeoff is observability because debugging request flow across POPs gets messy fast, so I’d keep the logic dead simple and deterministic.
Ellen
@Ellen1979 another good fit is stateless checks and tiny rewrites, but the implementation caveat is regional state: once behavior varies by POP, the failure cases get ugly and hard to reproduce.
Sarah
What is POP?
Another useful angle here: POP means point of presence, basically the provider’s edge location that handles a request near the user. One practical debugging signal is region-specific header or cache differences - if responses vary.
Sarah
That header/cache clue matters, especially when one POP serves stale config and another doesn’t. A simple region tag in logs usually saves time before you blame app code.
Sarah
POP is point of presence, basically an edge location close to the user that handles requests. In edge runtimes, POP-level differences can explain why behavior changes by region.
Sarah
