Replace build id in Pages data routes with deployment id by mischnic · Pull Request #88959 · vercel/next.js

mischnic · 2026-01-23T15:55:11Z

When a deployment id is available, don't put the data routes at _next/data/<BUILDID>/page.json, but at _next/data/page.json.
Deployment skew (forcing a MPA nav instead of a SPA nav if a deployment happened inbetween) is handled by comparing a header on the client side.

If you use output:export and set config.deploymentId (i.e. enable skew protection) you are still expected to set these headers.

Find the right place where the header should be added for prerendered static RSC responses (route manifest)

mischnic · 2026-01-23T15:55:47Z

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packages/next/src/server/base-server.ts

nextjs-bot · 2026-01-23T16:06:23Z

Tests Passed

nextjs-bot · 2026-01-23T16:13:33Z

Stats from current PR

🔴 1 regression

Metric	Canary	PR	Change	Trend
node_modules Size	463 MB	464 MB	🔴 +97.1 kB (+0%)	▁▁▁▁▁

📊 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 (Ready in log)	439ms	438ms	✓	▇█▇▅▇
Cold (First Request)	1.193s	1.141s	✓	▇█▇▆▇
Warm (Listen)	457ms	457ms	✓	▁█▁▁▁
Warm (Ready in log)	443ms	441ms	✓	▁█▁▁▁
Warm (First Request)	340ms	340ms	✓	█▂▆▁▁

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	457ms	✓	▁▁▁▁▁
Cold (Ready in log)	451ms	452ms	✓	▁▁▁▁▁
Cold (First Request)	1.890s	1.948s	✓	▁▁▁▁▁
Warm (Listen)	456ms	457ms	✓	▁▁▁▁▁
Warm (Ready in log)	449ms	450ms	✓	▁▁▁▁▁
Warm (First Request)	1.908s	1.886s	✓	▁▁▁▁▁

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	3.838s	3.940s	✓	▂█▂▁▂
Cached Build	3.868s	3.846s	✓	▂█▂▁▂

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.081s	14.097s	✓	▁▁▅▁▁
Cached Build	14.187s	14.224s	✓	▁▁▁▁▁
node_modules Size	463 MB	464 MB	🔴 +97.1 kB (+0%)	▁▁▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **434 kB** → **434 kB** ⚠️ +143 B

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

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	764 B	765 B	✓
Total	764 B	765 B	⚠️ +1 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	450 B	451 B	✓
Total	450 B	451 B	⚠️ +1 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
5528-HASH.js gzip	5.47 kB	N/A	-
6280-HASH.js gzip	54.4 kB	N/A	-
6335.HASH.js gzip	169 B	N/A	-
912-HASH.js gzip	4.53 kB	N/A	-
e8aec2e4-HASH.js gzip	62.5 kB	N/A	-
framework-HASH.js gzip	59.7 kB	59.7 kB	✓
main-app-HASH.js gzip	255 B	254 B	✓
main-HASH.js gzip	39 kB	39.1 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
262-HASH.js gzip	N/A	4.52 kB	-
2889.HASH.js gzip	N/A	169 B	-
5602-HASH.js gzip	N/A	5.48 kB	-
6948ada0-HASH.js gzip	N/A	62.5 kB	-
9544-HASH.js gzip	N/A	55.1 kB	-
Total	228 kB	229 kB	⚠️ +816 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	194 B	✓
_error-HASH.js gzip	183 B	180 B	🟢 3 B (-2%)
css-HASH.js gzip	331 B	330 B	✓
dynamic-HASH.js gzip	1.81 kB	1.81 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	351 B	352 B	✓
hooks-HASH.js gzip	384 B	383 B	✓
image-HASH.js gzip	580 B	581 B	✓
index-HASH.js gzip	260 B	260 B	✓
link-HASH.js gzip	2.49 kB	2.49 kB	✓
routerDirect..HASH.js gzip	320 B	319 B	✓
script-HASH.js gzip	386 B	386 B	✓
withRouter-HASH.js gzip	315 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.97 kB	7.97 kB	✅ -1 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	126 kB	126 kB	✓
page.js gzip	247 kB	248 kB	✓
Total	374 kB	374 kB	⚠️ +648 B

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	614 B	613 B	✓
middleware-r..fest.js gzip	156 B	155 B	✓
middleware.js gzip	33.1 kB	33.2 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.7 kB	34.8 kB	⚠️ +131 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	732 B	736 B	✓
Total	732 B	736 B	⚠️ +4 B

Build Cache

	Canary	PR	Change
0.pack gzip	3.76 MB	3.79 MB	🔴 +21.7 kB (+1%)
index.pack gzip	102 kB	102 kB	✓
index.pack.old gzip	101 kB	102 kB	🔴 +1.2 kB (+1%)
Total	3.97 MB	3.99 MB	⚠️ +22.9 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	311 kB	311 kB	✓
app-page-exp..prod.js gzip	166 kB	166 kB	✓
app-page-tur...dev.js gzip	311 kB	311 kB	✓
app-page-tur..prod.js gzip	166 kB	166 kB	✓
app-page-tur...dev.js gzip	307 kB	307 kB	✓
app-page-tur..prod.js gzip	164 kB	164 kB	✓
app-page.run...dev.js gzip	307 kB	307 kB	✓
app-page.run..prod.js gzip	164 kB	164 kB	✓
app-route-ex...dev.js gzip	70.2 kB	70.3 kB	✓
app-route-ex..prod.js gzip	48.8 kB	48.8 kB	✓
app-route-tu...dev.js gzip	70.2 kB	70.3 kB	✓
app-route-tu..prod.js gzip	48.8 kB	48.9 kB	✓
app-route-tu...dev.js gzip	69.8 kB	69.9 kB	✓
app-route-tu..prod.js gzip	48.6 kB	48.6 kB	✓
app-route.ru...dev.js gzip	69.8 kB	69.9 kB	✓
app-route.ru..prod.js gzip	48.6 kB	48.6 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	43.1 kB	43.2 kB	✓
pages-api-tu..prod.js gzip	32.8 kB	32.9 kB	✓
pages-api.ru...dev.js gzip	43.1 kB	43.2 kB	✓
pages-api.ru..prod.js gzip	32.8 kB	32.9 kB	✓
pages-turbo....dev.js gzip	52.4 kB	52.5 kB	✓
pages-turbo...prod.js gzip	39.3 kB	39.4 kB	✓
pages.runtim...dev.js gzip	52.3 kB	52.4 kB	✓
pages.runtim..prod.js gzip	39.3 kB	39.3 kB	✓
server.runti..prod.js gzip	62.5 kB	62.5 kB	✓
Total	2.77 MB	2.77 MB	⚠️ +1.2 kB

📝 Changed Files (25 files)

Files with changes:

app-page-exp..ntime.dev.js
app-page-exp..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page-tur..ntime.dev.js
app-page-tur..time.prod.js
app-page.runtime.dev.js
app-page.runtime.prod.js
app-route-ex..ntime.dev.js
app-route-ex..time.prod.js
app-route-tu..ntime.dev.js
app-route-tu..time.prod.js
app-route-tu..ntime.dev.js
app-route-tu..time.prod.js
app-route.runtime.dev.js
app-route.ru..time.prod.js
pages-api-tu..ntime.dev.js
pages-api-tu..time.prod.js
pages-api.runtime.dev.js
pages-api.ru..time.prod.js
... and 5 more

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packages/next/src/server/base-server.ts

packages/next/src/shared/lib/router/router.ts

packages/next/src/server/base-server.ts

codspeed-hq · 2026-01-26T13:44:14Z

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing mischnic/pages-data-route-dpl-header (7408d47) with canary (e78d35b)}

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

)" This reverts commit 6766a27.

)" (#89323) `test/e2e/middleware-redirects` has 404s on the data route

…8959)" (#89323) This reverts commit 303e38e.

Reapply #88959 Revert #89323 Closes PACK-6537 Closes PACK-6756 - Deployment skew (forcing a MPA nav instead of a SPA nav if a deployment happened inbetween) is handled by comparing a header on the client side. - The other case that used build ids was app router, which was changed to the same approach in #88855 - Then, when a deployment id is available, make the build id a constant - Particularly, this makes the rollout of this much easier as the data route paths stay the same (both in Next.js itself as well as in the builder) If you use `output:export` and set `config.deploymentId` (i.e. enable skew protection) you are still expected to set these headers.

…cel#88959)" (vercel#89323) `test/e2e/middleware-redirects` has 404s on the data route

…l#89325) Reapply vercel#88959 Revert vercel#89323 Closes PACK-6537 Closes PACK-6756 - Deployment skew (forcing a MPA nav instead of a SPA nav if a deployment happened inbetween) is handled by comparing a header on the client side. - The other case that used build ids was app router, which was changed to the same approach in vercel#88855 - Then, when a deployment id is available, make the build id a constant - Particularly, this makes the rollout of this much easier as the data route paths stay the same (both in Next.js itself as well as in the builder) If you use `output:export` and set `config.deploymentId` (i.e. enable skew protection) you are still expected to set these headers.

nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. tests type: next labels Jan 23, 2026

mischnic changed the title ~~WIOP debugging~~ Don't use build id for Pages data routes when dpl id is available Jan 23, 2026

vercel bot reviewed Jan 23, 2026

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mischnic force-pushed the mischnic/pages-data-route-dpl-header branch 2 times, most recently from 78c9786 to b6b5aed Compare January 26, 2026 09:31

mischnic changed the base branch from canary to graphite-base/88959 January 26, 2026 10:40

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch from b6b5aed to 7dc0d1e Compare January 26, 2026 10:40

mischnic changed the base branch from graphite-base/88959 to mischnic/pages-deployment-skew-test January 26, 2026 10:40

mischnic mentioned this pull request Jan 26, 2026

[test] Improve deployment skew test for Pages Router data routes #89038

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mischnic changed the base branch from mischnic/pages-deployment-skew-test to graphite-base/88959 January 26, 2026 10:46

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch from 7dc0d1e to b0a6c8e Compare January 26, 2026 10:56

mischnic force-pushed the graphite-base/88959 branch from f50ec09 to 152d38a Compare January 26, 2026 10:56

mischnic changed the base branch from graphite-base/88959 to mischnic/pages-deployment-skew-test January 26, 2026 10:56

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch from b0a6c8e to e1c0a15 Compare January 26, 2026 11:39

mischnic force-pushed the mischnic/pages-deployment-skew-test branch from 152d38a to 2b879e9 Compare January 26, 2026 11:39

Base automatically changed from mischnic/pages-deployment-skew-test to canary January 26, 2026 12:15

mischnic changed the base branch from canary to graphite-base/88959 January 26, 2026 12:15

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch from e1c0a15 to 7408d47 Compare January 26, 2026 13:23

mischnic changed the base branch from graphite-base/88959 to canary January 26, 2026 13:23

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mischnic mentioned this pull request Jan 26, 2026

[next] Add deployment id header for soft navigation responses vercel/vercel#14726

Closed

mischnic changed the title ~~Don't use build id for Pages data routes when dpl id is available~~ Replace build id in Pages data routes with dpl id is available Jan 26, 2026

mischnic changed the title ~~Replace build id in Pages data routes with dpl id is available~~ Replace build id in Pages data routes with deployment id Jan 26, 2026

mischnic mentioned this pull request Jan 27, 2026

Proper e2e test of function determinism #88908

Merged

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch 2 times, most recently from 21e3e41 to e1e10bd Compare January 28, 2026 10:38

mischnic marked this pull request as ready for review January 28, 2026 10:38

mischnic requested review from ijjk and timneutkens January 28, 2026 10:38

mischnic force-pushed the mischnic/pages-data-route-dpl-header branch 5 times, most recently from 9455b94 to 646bac7 Compare January 29, 2026 13:59

mischnic added 8 commits January 30, 2026 12:03

Client side changes

ed3fb98

Don't use build id with Pages data routes

6533b54

fixup

ef9b145

update unit tests

84c1ae2

cleanup test

cbb24a6

NEXT_NAV_DEPLOYMENT_ID_HEADER

ea3ff31

add header

30077f3

extend test

ac6933c

timneutkens approved these changes Jan 30, 2026

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mischnic force-pushed the mischnic/pages-data-route-dpl-header branch from 646bac7 to ac6933c Compare January 30, 2026 11:40

mischnic merged commit 6766a27 into canary Jan 30, 2026
289 of 292 checks passed

mischnic deleted the mischnic/pages-data-route-dpl-header branch January 30, 2026 17:22

mischnic added a commit that referenced this pull request Jan 30, 2026

Revert "Replace build id in Pages data routes with deployment id (#88959

6630f50

)" This reverts commit 6766a27.

ijjk pushed a commit that referenced this pull request Jan 30, 2026

Revert "Replace build id in Pages data routes with deployment id (#88959

303e38e

)" (#89323) `test/e2e/middleware-redirects` has 404s on the data route

mischnic added a commit that referenced this pull request Jan 30, 2026

Reapply "Replace build id in Pages data routes with deployment id (#8…

eaf3516

…8959)" (#89323) This reverts commit 303e38e.

mischnic mentioned this pull request Jan 30, 2026

Handle Pages data route skew with deployment id header, take 2 #89325

Merged

bgub pushed a commit to bgub/next.js that referenced this pull request Feb 5, 2026

Revert "Replace build id in Pages data routes with deployment id (ver…

75f0c5b

…cel#88959)" (vercel#89323) `test/e2e/middleware-redirects` has 404s on the data route

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Replace build id in Pages data routes with deployment id#88959

Replace build id in Pages data routes with deployment id#88959
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