[▲ Vercel Community](/) · [Categories](/categories) · [Latest](/latest) · [Top](/top) · [Live](/live) [Help](/c/help/9) # Why Vercel Edge requests and FDT usage spike for static chunks 1 view · 0 likes · 4 posts Colin J (@colin-jiang) · 2026-04-08 ## Problem My edge requests and FDT (Fast Data Transfer) usage doubled last month while my traffic on other analytics platforms show no increase in traffic. What’s strange is it seems it all comes from very spiky usage from `_next/static/chunks` files, while the rest of my routes look normal. ## Observations - The spikes are not correlated with deployments. - When I check my firewall traffic logs, the challenge/deny/logged traffic isn’t spiky, but the allowed traffic is showing these spikes. - I had bot protection on. Reached out to support but I’m also posting here cause my Vercel costs are becoming unsustainable with this new usage spikes (monthly costs have doubled). Especially since it doesn’t seem correlated with my traffic at all. So I’m hoping to get this resolved ASAP.  Chunks files are very spiky in usage.  Normal page routes have no spiky usage.  ## Environment I’m using `Next.js` `14.2.30` with Pages Router and hosted on Vercel. Pauline P. Narvas (@pawlean) · 2026-04-08 Hey Colin! The spiky Edge request pattern on your `_next/static/chunks` files is characteristic of bot traffic targeting your static assets. Could you enable *Attack Challenge Mode* in your Firewall settings? This won’t count blocked requests against your usage. You can also set up custom WAF rules to block common bot patterns: - Block requests with suspicious user agents - Rate limit by IP address - Block requests missing expected headers - Consider implementing Edge Middleware for more sophisticated rate limiting - Review your `Cache-Control` headers - ensure chunks are properly cached With cost management concerns, make sure you set up [Spend Management](http://vercel.com/docs/spend-management) alerts to notify you of usage spikes. The fact that your firewall shows this as allowed traffic suggests the bots may be sophisticated enough to pass basic challenges. Attack Challenge Mode with custom rules should help identify and block this traffic more effectively. vercel.com/docs/vercel-firewall/attack-challenge-mode Colin J (@colin-jiang) · 2026-04-08 Attack Challenge Mode forces all traffic to complete a challenge though which I’d like to avoid. I had Bot protection turned on already. Since I don’t have observability plus I don’t have custom querying, so it’s hard to create a custom WAF rule to catch these bots. Could we have someone take a look at my support case and help set this up? Thanks Pauline P. Narvas (@pawlean) · 2026-04-09 Do you have a case number I can share internally? Since you've already got a pending case, one of our support engineers will get back to you!