7 Infra Improvement Strategies to Prevent Next.js Deployment Build Failures in 2026

7 Infra Improvement Strategies to Prevent Next.js Deployment Build Failures in 2026 Recently, our team's deployment pipeline started showing serious instability. Specifically, we encountered recurring build failures related to the chat build. As a result, the entire development team was preoccupied with battling these build failures. Attempts and Pitfalls Initially, I thought the --preload detection logic was the problem. I modified it to detect only specific lines, but this ended up causing issues in other areas. The recurring chat build failures were actually caused by the next.config file not properly recognizing file extensions. I modified it to allow extensions like .mjs , .js , .ts , and .cjs , but even that didn't work correctly at first, leading to some wasted effort. # .github/workflows/deploy.yml (Excerpt from initial version) - name : Run Preload Detection run : | # ... existing logic ... if [[ "$LINE" == *"some_pattern"* ]]; then echo "Preload detected" # ... fi I modified it to detect only specific lines like the above, which led to unintended behavior. // next.config.js (Initial configuration) module . exports = { // ... experimental : { // ... }, // ... }; Regarding extensions, I initially allowed only a few types, and only after experiencing chat build failures did I modify it to support more extensions. Root Causes In the end, it was a combination of several complex issues. There were flaws in the --preload detection logic, and the range of supported extensions in the next.config file was too narrow, which was the direct cause of the chat build failures. Additionally, there was confusion arising from the chat server builds being inconsistent between P1/P2 and P0 stages. Problems also occurred because the .next directory was not preserved, and the smoke gate was too lenient, failing to catch build failures. Finally, there was an unexpected side effect where the next/font/google library caused GCE outbound connection errors. Solutions To address these