## What this fixes
Integrating @axiomhq/nextjs into a Next.js 15 project following the official docs, the Vercel production build fails with: Module build failed: UnhandledSchemeError: Reading from "node:crypto" is not handled by plugins (Unhandled scheme). The import trace points at @axiomhq/nextjs dist/esm/lib/node-utils.js pulled in through routeHandler.js. Removing the instrumentation file makes the build pass, which points at the instrumentation setup as the trigger.
## The fix
The Next.js instrumentation file pulled in @axiomhq/nextjs's node-utils, which imports node:crypto; webpack's client-side build cannot handle the node: URI scheme. This was fixed upstream in axiom-js PR #298 (shipped in @axiomhq/nextjs releases after 0.1.2). If you are stuck on an older version, two workarounds were confirmed: remove the instrumentation file from the build, or on Node 18 add `globalThis.crypto ??= require("node:crypto").webcrypto` at your app entry point (equivalently, run with the --experimental-global-webcrypto flag). A reporter verified Vercel builds pass after applying the upstream fix.
Source: https://github.com/axiomhq/axiom-js/issues/283
## Why it happens
The thread above nails the cause, so the fix addresses that directly rather than symptoms. Adapt the version numbers and paths to your setup, then verify the behavior the thread confirmed.
## Source
https://github.com/axiomhq/axiom-js/issues/283