Move Ready in time before handler initialization #88235

timneutkens · 2026-01-07T16:50:25Z

Move "Ready in X" log before config loading and eliminate duplicate `loadConfig` calls

What?

Reorder the dev server startup flow so the "Ready in X" log appears before loading the user's next.config.js, and eliminate duplicate loadConfig calls in both dev and build paths.

Why?

Previously, the "Ready in X" time included the time spent loading and evaluating the user's next.config.js file. This made the framework appear slower than it actually is, especially for projects with complex config files or slow config evaluation.

Additionally, config was being loaded twice:

Dev server: Once in getStartServerInfo() just for logging, then again in getRequestHandlers()
Build: Once for the main build, then again in getStartServerInfo() just for logging

How?

Before:

1. getStartServerInfo() → loadConfig #1 (slow - blocks on next.config.js)
2. logStartInfo() → logs version, URLs, experimental features
3. "Ready in X" ← time includes config loading
4. getRequestHandlers() → loadConfig #2

After:

1. logStartInfo() → logs version, URLs, envInfo (no config needed)
2. "Ready in X" ← reflects actual framework startup time
3. getRequestHandlers() → loadConfig (once)
4. logExperimentalInfo() → logs experimental features

Changes:

Split logStartInfo into two functions:
- logStartInfo() - basic info (version, URLs, env) - no config needed
- logExperimentalInfo() - experimental features and cacheComponents
Removed getStartServerInfo() which was loading config unnecessarily
Added experimentalFeatures and cacheComponents to ServerInitResult so they can be passed back after config loads
In build, added reportExperimentalFeatures callback to the existing loadConfig call instead of loading config twice

timneutkens · 2026-01-07T16:50:47Z

Move Ready in time before handler initialization #88235 : 2 dependent PRs (#88239 , #88283 ) 👈 (View in Graphite)
Remove loadConfig from main development process, pass value from child process #88230
canary

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nextjs-bot · 2026-01-07T16:54:18Z

Tests Passed

packages/next/src/server/lib/start-server.ts

nextjs-bot · 2026-01-07T17:08:39Z

Stats from current PR

🔴 1 regression

Metric	Canary	PR	Change	Trend
Warm (First Request)	351ms	405ms	🔴 +54ms (+15%)	▂█▁▁▄

📊 All Metrics

📖 Metrics Glossary

Dev Server Metrics:

Listen = TCP port starts accepting connections
First Request = HTTP server returns successful response
Cold = Fresh build (no cache)
Warm = With cached build artifacts

Build Metrics:

Fresh = Clean build (no .next directory)
Cached = With existing .next directory

Change Thresholds:

Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
Size: Changes < 1KB AND < 1% are insignificant
All other changes are flagged to catch regressions

⚡ Dev Server

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	455ms	✓	▁█▁▁▁
Cold (First Request)	1.113s	1.199s	✓	█▂█▇▇
Warm (Listen)	457ms	456ms	✓	▁██▁█
Warm (First Request)	351ms	405ms	🔴 +54ms (+15%)	▂█▁▁▄

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	454ms	✓	▁▁▁▁▁
Cold (First Request)	1.815s	1.824s	✓	▃▄▄▃▁
Warm (Listen)	455ms	456ms	✓	▁▁▁▁▁
Warm (First Request)	1.833s	1.814s	✓	▃▃▃▂▁

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	4.150s	4.163s	✓	▁█▁▁▁
Cached Build	4.180s	4.196s	✓	▂█▁▂▁

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	13.782s	13.815s	✓	▂▂▁▁▁
Cached Build	13.937s	13.901s	✓	▁▂▂▁▁
node_modules Size	457 MB	457 MB	✓	█████

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **431 kB** → **431 kB** ⚠️ +2 B

82 files with content-based hashes (individual files not comparable between builds)

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	785 B	788 B	✓
Total	785 B	788 B	⚠️ +3 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	451 B	451 B	✓
Total	451 B	451 B	✓

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
2086.HASH.js gzip	169 B	N/A	-
2161-HASH.js gzip	5.4 kB	N/A	-
2747-HASH.js gzip	4.48 kB	N/A	-
4322-HASH.js gzip	52.7 kB	N/A	-
ec793fe8-HASH.js gzip	62.3 kB	N/A	-
framework-HASH.js gzip	59.8 kB	59.8 kB	✓
main-app-HASH.js gzip	251 B	254 B	🔴 +3 B (+1%)
main-HASH.js gzip	38.6 kB	38.9 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
1596.HASH.js gzip	N/A	169 B	-
2658-HASH.js gzip	N/A	52.5 kB	-
6349-HASH.js gzip	N/A	4.46 kB	-
7019-HASH.js gzip	N/A	5.42 kB	-
b17a3386-HASH.js gzip	N/A	62.3 kB	-
Total	225 kB	225 kB	⚠️ +160 B

Polyfills

	Canary	PR	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Total	39.4 kB	39.4 kB	✓

Pages

	Canary	PR	Change
_app-HASH.js gzip	194 B	193 B	✓
_error-HASH.js gzip	182 B	182 B	✓
css-HASH.js gzip	336 B	335 B	✓
dynamic-HASH.js gzip	1.8 kB	1.8 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	352 B	349 B	✓
hooks-HASH.js gzip	385 B	384 B	✓
image-HASH.js gzip	580 B	580 B	✓
index-HASH.js gzip	259 B	258 B	✓
link-HASH.js gzip	2.5 kB	2.51 kB	✓
routerDirect..HASH.js gzip	319 B	317 B	✓
script-HASH.js gzip	385 B	387 B	✓
withRouter-HASH.js gzip	316 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.97 kB	7.96 kB	✅ -8 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	124 kB	124 kB	✓
page.js gzip	240 kB	241 kB	✓
Total	364 kB	365 kB	⚠️ +1.03 kB

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	652 B	655 B	✓
middleware-r..fest.js gzip	155 B	156 B	✓
middleware.js gzip	32.7 kB	33 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.4 kB	34.6 kB	⚠️ +242 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	738 B	738 B	✓
Total	738 B	738 B	✓

Build Cache

	Canary	PR	Change
0.pack gzip	3.63 MB	3.63 MB	🔴 +6.38 kB (+0%)
index.pack gzip	98.5 kB	98.9 kB	✓
index.pack.old gzip	99.8 kB	99.8 kB	✓
Total	3.83 MB	3.83 MB	⚠️ +6.75 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	303 kB	303 kB	✓
app-page-exp..prod.js gzip	158 kB	158 kB	✓
app-page-tur...dev.js gzip	303 kB	303 kB	✓
app-page-tur..prod.js gzip	158 kB	158 kB	✓
app-page-tur...dev.js gzip	299 kB	299 kB	✓
app-page-tur..prod.js gzip	156 kB	156 kB	✓
app-page.run...dev.js gzip	300 kB	300 kB	✓
app-page.run..prod.js gzip	156 kB	156 kB	✓
app-route-ex...dev.js gzip	68.7 kB	68.7 kB	✓
app-route-ex..prod.js gzip	47.5 kB	47.5 kB	✓
app-route-tu...dev.js gzip	68.7 kB	68.7 kB	✓
app-route-tu..prod.js gzip	47.6 kB	47.6 kB	✓
app-route-tu...dev.js gzip	68.3 kB	68.3 kB	✓
app-route-tu..prod.js gzip	47.3 kB	47.3 kB	✓
app-route.ru...dev.js gzip	68.3 kB	68.3 kB	✓
app-route.ru..prod.js gzip	47.3 kB	47.3 kB	✓
dist_client_...dev.js gzip	324 B	324 B	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
dist_client_...dev.js gzip	317 B	317 B	✓
pages-api-tu...dev.js gzip	41.1 kB	41.1 kB	✓
pages-api-tu..prod.js gzip	31.2 kB	31.2 kB	✓
pages-api.ru...dev.js gzip	41 kB	41 kB	✓
pages-api.ru..prod.js gzip	31.2 kB	31.2 kB	✓
pages-turbo....dev.js gzip	50.8 kB	50.8 kB	✓
pages-turbo...prod.js gzip	38.2 kB	38.2 kB	✓
pages.runtim...dev.js gzip	50.7 kB	50.7 kB	✓
pages.runtim..prod.js gzip	38.2 kB	38.2 kB	✓
server.runti..prod.js gzip	62.2 kB	62.2 kB	✓
Total	2.68 MB	2.68 MB	⚠️ +1 B

packages/next/src/bin/next.ts

…ces different output format (adds decimal places)

## Move "Ready in X" log before config loading and eliminate duplicate `loadConfig` calls ### What? Reorder the dev server startup flow so the "Ready in X" log appears before loading the user's `next.config.js`, and eliminate duplicate `loadConfig` calls in both dev and build paths. ### Why? Previously, the "Ready in X" time included the time spent loading and evaluating the user's `next.config.js` file. This made the framework appear slower than it actually is, especially for projects with complex config files or slow config evaluation. Additionally, config was being loaded twice: - **Dev server**: Once in `getStartServerInfo()` just for logging, then again in `getRequestHandlers()` - **Build**: Once for the main build, then again in `getStartServerInfo()` just for logging ### How? **Before:** ``` 1. getStartServerInfo() → loadConfig #1 (slow - blocks on next.config.js) 2. logStartInfo() → logs version, URLs, experimental features 3. "Ready in X" ← time includes config loading 4. getRequestHandlers() → loadConfig vercel#2 ``` **After:** ``` 1. logStartInfo() → logs version, URLs, envInfo (no config needed) 2. "Ready in X" ← reflects actual framework startup time 3. getRequestHandlers() → loadConfig (once) 4. logExperimentalInfo() → logs experimental features ``` **Changes:** - Split `logStartInfo` into two functions: - `logStartInfo()` - basic info (version, URLs, env) - no config needed - `logExperimentalInfo()` - experimental features and cacheComponents - Removed `getStartServerInfo()` which was loading config unnecessarily - Added `experimentalFeatures` and `cacheComponents` to `ServerInitResult` so they can be passed back after config loads - In build, added `reportExperimentalFeatures` callback to the existing `loadConfig` call instead of loading config twice --------- Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>

nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. type: next labels Jan 7, 2026

timneutkens mentioned this pull request Jan 7, 2026

Remove loadConfig from main development process, pass value from child process #88230

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vercel bot reviewed Jan 7, 2026

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packages/next/src/server/lib/start-server.ts Outdated Show resolved Hide resolved

timneutkens mentioned this pull request Jan 7, 2026

Split Ready in log from next.config.js loading #88239

Closed

lukesandberg reviewed Jan 7, 2026

View reviewed changes

packages/next/src/bin/next.ts Show resolved Hide resolved

timneutkens force-pushed the 01-07-move_ready_in_time_before_handler_initialization branch from 51c96d7 to 53bb852 Compare January 8, 2026 09:01

timneutkens force-pushed the 01-07-remove_loadconfig_from_main_development_process_pass_value_from_child_process branch from 06575ea to cab0c4e Compare January 8, 2026 09:01

timneutkens force-pushed the 01-07-move_ready_in_time_before_handler_initialization branch 2 times, most recently from 765ac1c to c810b98 Compare January 8, 2026 09:22

Base automatically changed from 01-07-remove_loadconfig_from_main_development_process_pass_value_from_child_process to canary January 8, 2026 11:00

timneutkens added 16 commits January 8, 2026 12:01

Move Ready in time before handler initialization

4ac9fb4

Split Ready in log from next.config.js loading

06085bf

Add retry as this value is not immediately available

6e56242

Add retry

db6bb39

Update index.test.ts

070d513

Update index.test.ts

f6a1737

Update index.test.ts

0f3d884

Update index.test.ts

1e6c501

Update isolated-dev-build.test.ts

f0948e3

Update start-no-build.test.ts

8920ae0

Update index.test.ts

39ca6a8

Update i18n-hybrid.test.ts

aef10d5

Update multiple-lockfiles.test.ts

400b775

Update log-file.test.ts

061486e

Update index.test.ts

5e7b7c6

Update instrumentation-order.test.ts

874a63a

timneutkens added 11 commits January 8, 2026 12:01

Update typed-routes-validator.test.ts

e6af6fe

Update index.test.ts

5ad67dd

Update index.test.ts

e961a06

Update build-output-prerender.test.ts

6d01b71

Update proxy-with-middleware.test.ts

9567cb7

Update app-middleware.test.ts

fc5318d

Update cache-components-console-patch.test.ts

5a0ecd1

Update deprecation-warnings.test.ts

5bf4937

Update persistent-caching-migration.test.ts

7a61873

Update typed-routes-validator.test.ts

8821555

Update index.test.ts

d0b6e96

timneutkens force-pushed the 01-07-move_ready_in_time_before_handler_initialization branch from c810b98 to 4ac9fb4 Compare January 8, 2026 11:01

timneutkens and others added 9 commits January 8, 2026 13:17

Update server-components-hmr-cache.test.ts

1cdf445

Update log-file.test.ts

03c1b16

Update build-output-prerender.test.ts

7ba9811

Update dev-output.test.ts

e9386a6

Update build-output-prerender.test.ts

76b5fad

Update server-components-hmr-cache.test.ts

cdfc9e1

Update index.test.ts

25f52b4

Address feedback from @lukesandberg

d0f14d1

Fix: Duration formatting logic duplicated, but durationToString produ…

4788f91

…ces different output format (adds decimal places)

nextjs-bot added the tests label Jan 8, 2026

timneutkens marked this pull request as ready for review January 8, 2026 15:51

timneutkens requested a review from feedthejim January 8, 2026 15:51

Update index.ts

31eb324

timneutkens mentioned this pull request Jan 8, 2026

Stats Action: Add ready in time #88283

Merged

feedthejim approved these changes Jan 8, 2026

View reviewed changes

timneutkens merged commit fd2bd29 into canary Jan 8, 2026
163 checks passed

timneutkens deleted the 01-07-move_ready_in_time_before_handler_initialization branch January 8, 2026 18:09

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Move Ready in time before handler initialization #88235

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Move "Ready in X" log before config loading and eliminate duplicate loadConfig calls

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Move "Ready in X" log before config loading and eliminate duplicate `loadConfig` calls

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