Next.js 16 (Turbopack) build hangs at 'Running TypeScript...' — killed at ~45min platform limit - Help

We're seeing a recurring build hang on Vercel (Hobby plan). Six separate deployments across four different commits have now failed with an identical signature: Turbopack compiles successfully every time (logged as "Compiled successfully in X min"), then "Running TypeScript ..." is logged next, then no further output ever appears (no compiler error, no warning, no OOM message, no process signal) until the build is killed at Vercel's approximately 45-minute platform limit and marked "Error". Environment: Next.js 16.2.10 (Turbopack), TypeScript 5.9.3, Node.js 24.x, Standard build machine (2 cores, 8 GB), region iad1, npm with a committed package-lock.json. What makes this hard to pin down: both cached and confirmed cold/no-cache builds have failed with the identical signature (one failing build had no cache-restore log line at all, a genuinely fresh install, which rules out stale or corrupted cache as the sole cause); the same source tree, byte-for-byte identical, has both succeeded (9 minutes, normal) and failed (45+ minutes, killed) across different attempts, including cases using the same underlying cache source; and two of the failing commits differ from each other only by two added markdown documentation files, zero code, config, or dependency change, yet still failed identically. On our end, we've confirmed: tsc --noEmit against the exact source completes in well under a minute locally, with zero errors; a full local next build (clean, no cache) completes successfully end-to-end in under 10 minutes, including its own TypeScript-checking step; lint is clean, and our full test suite, 3,227 tests, passes; and production has remained healthy throughout on the previous successful deployment, since Vercel never promotes a failed build, so the live site was never affected. Successful builds on this same project normally complete the TypeScript-check step in about 67 seconds. Every failure stalls at roughly 40x that duration before being killed, with zero diagnostic output the entire time. We're not certain whether this is Vercel's build infrastructure, Turbopack's TypeScript worker, something in our own dependency tree, or something else entirely, since we don't have visibility into what's happening inside the build container during the stall. Has anyone else run into this specific pattern, a silent hang at "Running TypeScript ..." independent of cache state and independent of the actual code diff? Is there a supported way to get more diagnostic output from a stalled build, or a known workaround, that doesn't involve disabling TypeScript checks or Next's generated route-type validation? Any pointers would be appreciated.

Leaderboard Winner

Hi Shulsberg 5694,

Since the stall happens after Compiled successfully and exactly at Running TypeScript, I’d try to split Next’s built-in type phase into smaller checkpoints on Vercel rather than treating the whole next build as one black box.

For one preview branch, I’d temporarily make the build command/script print each step:

set -eux
node -v
npm -v
npx next info --verbose
time npx next typegen
time npx tsc --noEmit --pretty false --extendedDiagnostics
time npx next build --debug

next typegen is the useful extra check here because plain tsc --noEmit may not validate Next’s generated route types unless those types have been generated first.

The result should narrow it down:

If next typegen hangs, the issue is likely around route type generation/config loading.
If tsc --noEmit hangs only on Vercel, the issue is closer to TypeScript/project/env in the build container.
If both finish quickly but next build still hangs at Running TypeScript, that points more toward Next’s internal build/type-check step.

I’d also run one canary build with Webpack as a bisect, not necessarily as the long-term fix:

npx next build --webpack --debug

If Webpack succeeds consistently while Turbopack intermittently hangs on the same commit, that is useful evidence for a Next/Turbopack build-path issue. If Webpack hangs too, I’d look more at Node/build-container differences. As another control, try pinning Node to 22.x for one preview build, since you’re currently on Node 24.x.

For local reproduction against Vercel settings, this is also worth trying:

vercel pull --environment=preview
vercel build --debug

I would avoid typescript.ignoreBuildErrors unless you already have an external gated type-check step, because that bypasses the check rather than making it more diagnosable.

The most useful follow-up would be the last checkpoint printed from the temporary build command above.