instanceof Request check in @aws-amplify/adapter-nextjs breaks on AWS Lambda (OpenNext/SST)

[thrawny]

Before opening, please confirm:

• I have searched for duplicate or closed issues and discussions.
• I have read the guide for submitting bug reports.
• I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.

JavaScript Framework

Next.js

Amplify APIs

Authentication

Amplify Version

v6

Amplify Categories

auth

Backend

Other

Environment information

System:
OS: macOS 15.5
CPU: (8) arm64 Apple M3
Memory: 114.50 MB / 16.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 24.3.0 - ~/.asdf/installs/nodejs/v24.3.0/bin/node
Yarn: 1.22.22 - ~/.asdf/installs/nodejs/v24.3.0/bin/yarn
npm: 11.4.2 - ~/.asdf/plugins/nodejs/shims/npm
pnpm: 10.12.4 - ~/.asdf/installs/nodejs/v24.3.0/bin/pnpm
Browsers:
Chrome: 138.0.7204.50
Safari: 18.5
npmPackages:
@ampproject/toolbox-optimizer: undefined ()
@aws-amplify/adapter-nextjs: ^1.6.4 => 1.6.4
@aws-amplify/adapter-nextjs/api: undefined ()
@aws-amplify/adapter-nextjs/data: undefined ()
@aws-amplify/auth: ^6.13.1 => 6.13.1
@aws-amplify/auth/cognito: undefined ()
@aws-amplify/auth/cognito/server: undefined ()
@aws-amplify/auth/enable-oauth-listener: undefined ()
@aws-amplify/auth/server: undefined ()
@aws-sdk/client-cognito-identity-provider: ^3.839.0 => 3.839.0
@babel/core: undefined ()
@babel/runtime: 7.22.5
@edge-runtime/cookies: 6.0.0
@edge-runtime/ponyfill: 4.0.0
@edge-runtime/primitives: 6.0.0
@eslint/eslintrc: ^3 => 3.3.1
@hapi/accept: undefined ()
@mswjs/interceptors: undefined ()
@napi-rs/triples: undefined ()
@next/font: undefined ()
@opentelemetry/api: undefined ()
@tailwindcss/postcss: ^4 => 4.1.11
@types/jsonwebtoken: ^9.0.10 => 9.0.10
@types/node: ^20 => 20.19.2
@types/react: ^19 => 19.1.8
@types/react-dom: ^19 => 19.1.6
@typescript/vfs: undefined ()
@vercel/nft: undefined ()
@vercel/og: 0.6.8
acorn: undefined ()
amphtml-validator: undefined ()
anser: undefined ()
assert: undefined ()
async-retry: undefined ()
async-sema: undefined ()
aws-amplify: ^6.15.1 => 6.15.1
aws-amplify/adapter-core: undefined ()
aws-amplify/adapter-core/internals: undefined ()
aws-amplify/analytics: undefined ()
aws-amplify/analytics/kinesis: undefined ()
aws-amplify/analytics/kinesis-firehose: undefined ()
aws-amplify/analytics/personalize: undefined ()
aws-amplify/analytics/pinpoint: undefined ()
aws-amplify/api: undefined ()
aws-amplify/api/internals: undefined ()
aws-amplify/api/server: undefined ()
aws-amplify/auth: undefined ()
aws-amplify/auth/cognito: undefined ()
aws-amplify/auth/cognito/server: undefined ()
aws-amplify/auth/enable-oauth-listener: undefined ()
aws-amplify/auth/server: undefined ()
aws-amplify/data: undefined ()
aws-amplify/data/server: undefined ()
aws-amplify/datastore: undefined ()
aws-amplify/in-app-messaging: undefined ()
aws-amplify/in-app-messaging/pinpoint: undefined ()
aws-amplify/push-notifications: undefined ()
aws-amplify/push-notifications/pinpoint: undefined ()
aws-amplify/storage: undefined ()
aws-amplify/storage/s3: undefined ()
aws-amplify/storage/s3/server: undefined ()
aws-amplify/storage/server: undefined ()
aws-amplify/utils: undefined ()
babel-packages: undefined ()
browserify-zlib: undefined ()
browserslist: undefined ()
buffer: undefined ()
bytes: undefined ()
ci-info: undefined ()
cli-select: undefined ()
client-only: 0.0.1
commander: undefined ()
comment-json: undefined ()
compression: undefined ()
conf: undefined ()
constants-browserify: undefined ()
content-disposition: undefined ()
content-type: undefined ()
cookie: undefined ()
cross-spawn: undefined ()
crypto-browserify: undefined ()
css.escape: undefined ()
data-uri-to-buffer: undefined ()
debug: undefined ()
devalue: undefined ()
domain-browser: undefined ()
edge-runtime: undefined ()
eslint: ^9 => 9.30.0
eslint-config-next: 15.3.4 => 15.3.4
events: undefined ()
find-up: undefined ()
fresh: undefined ()
glob: undefined ()
gzip-size: undefined ()
http-proxy: undefined ()
http-proxy-agent: undefined ()
https-browserify: undefined ()
https-proxy-agent: undefined ()
icss-utils: undefined ()
ignore-loader: undefined ()
image-size: undefined ()
is-animated: undefined ()
is-docker: undefined ()
is-wsl: undefined ()
jest-worker: undefined ()
json5: undefined ()
jsonwebtoken: ^9.0.2 => undefined (9.0.2, )
loader-runner: undefined ()
loader-utils: undefined ()
lodash.curry: undefined ()
lru-cache: undefined ()
mini-css-extract-plugin: undefined ()
nanoid: undefined ()
native-url: undefined ()
neo-async: undefined ()
next: 15.3.4 => 15.3.4
node-html-parser: undefined ()
ora: undefined ()
os-browserify: undefined ()
p-limit: undefined ()
p-queue: undefined ()
patch-package: ^8.0.0 => 8.0.0
path-browserify: undefined ()
path-to-regexp: undefined ()
picomatch: undefined ()
postcss-flexbugs-fixes: undefined ()
postcss-modules-extract-imports: undefined ()
postcss-modules-local-by-default: undefined ()
postcss-modules-scope: undefined ()
postcss-modules-values: undefined ()
postcss-preset-env: undefined ()
postcss-safe-parser: undefined ()
postcss-scss: undefined ()
postcss-value-parser: undefined ()
prettier: ^3.6.2 => 3.6.2
process: undefined ()
punycode: undefined ()
querystring-es3: undefined ()
raw-body: undefined ()
react: ^19.0.0 => 19.1.0
react-builtin: undefined ()
react-dom: ^19.0.0 => 19.1.0
react-dom-builtin: undefined ()
react-dom-experimental-builtin: undefined ()
react-experimental-builtin: undefined ()
react-is: 19.2.0-canary-3fbfb9ba-20250409
react-refresh: 0.12.0
react-server-dom-turbopack-builtin: undefined ()
react-server-dom-turbopack-experimental-builtin: undefined ()
react-server-dom-webpack-builtin: undefined ()
react-server-dom-webpack-experimental-builtin: undefined ()
regenerator-runtime: 0.13.4
sass-loader: undefined ()
scheduler-builtin: undefined ()
scheduler-experimental-builtin: undefined ()
schema-utils: undefined ()
semver: undefined ()
send: undefined ()
server-only: 0.0.1
setimmediate: undefined ()
shell-quote: undefined ()
source-map: undefined ()
source-map08: undefined ()
sst: 3.17.8 => 3.17.8
stacktrace-parser: undefined ()
stream-browserify: undefined ()
stream-http: undefined ()
string-hash: undefined ()
string_decoder: undefined ()
strip-ansi: undefined ()
superstruct: undefined ()
tailwindcss: ^4 => 4.1.11
tar: undefined ()
terser: undefined ()
text-table: undefined ()
timers-browserify: undefined ()
tty-browserify: undefined ()
typescript: ^5 => 5.8.3
ua-parser-js: undefined ()
unistore: undefined ()
util: undefined ()
vm-browserify: undefined ()
watchpack: undefined ()
web-vitals: undefined ()
webpack: undefined ()
webpack-sources: undefined ()
ws: undefined ()
zod: undefined ()
zod-validation-error: undefined ()
npmGlobalPackages:
@google/gemini-cli: 0.1.5
corepack: 0.33.0
npm: 11.4.2
pnpm: 10.12.4
prettier: 3.6.2
sst: 3.17.8
yarn: 1.22.22

Describe the bug

instanceof Request check in @aws-amplify/adapter-nextjs breaks on AWS Lambda (OpenNext/SST)

Summary

When deploying a Next.js App Router project using the Amplify adapter (@aws-amplify/adapter-nextjs) on AWS Lambda (via OpenNext/SST), authentication API routes (e.g., /api/auth/sign-in) work on the first (cold) request, but subsequent (warm) requests return 500 errors:

Error: Invalid request and context/response combination. The request cannot be handled.

---

Root Cause

• The adapter uses this type guard:

  function isNextRequest(request) {
    return request instanceof Request && 'nextUrl' in request;
  }

• In Lambda/serverless environments, due to bundling and process reuse, the Request constructor reference may differ between invocations. As a result, instanceof Request fails even for valid Next.js NextRequest objects.
• This causes the adapter to reject valid requests, leading to 500 errors on all but the first invocation.

Expected behavior

The /api/auth/... endpoints should be stable and work in Lambda/OpenNext deployments.

Reproduction steps

1. Configure server side auth as described here: https://docs.amplify.aws/react/build-a-backend/server-side-rendering/
2. Deploy using OpenNext/SST to AWS Lambda.
3. Make a request to an auth route (e.g., /api/auth/sign-in) – it works on cold start.
4. Make a second request – it fails with a 500 and the error above.

Code Snippet

Log output

aws-exports.js

No response

Manual configuration

No response

Additional configuration

No response

Mobile Device

No response

Mobile Operating System

No response

Mobile Browser

No response

Mobile Browser Version

No response

Additional information and screenshots

No response

[soberm]

Hi @thrawny, thanks for reporting this issue. We will try to reproduce and come back to you once we have an update.