[world-vercel] Fix stream read hang from hold-back buffer by VaguelySerious · Pull Request #1781 · vercel/workflow

VaguelySerious · 2026-04-16T19:52:04Z

Summary

Fixes the production hang introduced by #1742. The hold-back buffer inside the ReadableStream pull loop caused all Vercel Prod e2e tests to fail with timeouts — the readableStreamWorkflow test hung for 30s getting empty content, which cascaded into random subsequent test timeouts.

Replace the for(;;) hold-back buffer inside pull with a full-response read via arrayBuffer()
Strip the control frame after reading, reconnect if server signaled timeout, then return a ReadableStream with the collected data
Remove unused concatUint8Arrays helper
Fix test mocks that returned never-closing ReadableStreams (which now hang since get() calls arrayBuffer())

Test plan

All 40 unit tests pass (29 streamer + 11 reconnect)
Vercel Prod e2e tests should no longer hang

🤖 Generated with Claude Code

The hold-back buffer inside the ReadableStream pull loop hangs in production — the for(;;) loop reads multiple chunks without yielding, and something about the proxy/byte-stream wrapper environment causes the consumer to never receive data. Replace with full-response read via arrayBuffer(), strip the control frame, reconnect if needed, then return a ReadableStream with the collected data. This is simpler and avoids the nested-stream issue. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vercel · 2026-04-16T19:52:06Z

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Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Apr 16, 2026 7:56pm
example-nextjs-workflow-webpack	Ready	Preview, Comment	Apr 16, 2026 7:56pm
example-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-astro-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-express-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-fastify-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-hono-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-nitro-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-nuxt-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-sveltekit-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workbench-vite-workflow	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workflow-docs	Ready	Preview, Comment, Open in v0	Apr 16, 2026 7:56pm
workflow-swc-playground	Ready	Preview, Comment	Apr 16, 2026 7:56pm
workflow-web	Ready	Preview, Comment	Apr 16, 2026 7:56pm

changeset-bot · 2026-04-16T19:52:11Z

🦋 Changeset detected

Latest commit: 77c6d7d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-vercel	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/web	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	Patch
@workflow/web-shared	Patch
@workflow/ai	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

github-actions · 2026-04-16T19:52:14Z

🧪 E2E Test Results

❌ Some tests failed

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	914	9	67	990
✅ 💻 Local Development	994	0	86	1080
✅ 📦 Local Production	994	0	86	1080
✅ 🐘 Local Postgres	994	0	86	1080
✅ 🪟 Windows	90	0	0	90
❌ 🌍 Community Worlds	133	98	0	231
✅ 📋 Other	252	0	18	270
Total	4371	107	343	4821

❌ Failed Tests

▲ Vercel Production (9 failed)

example (1 failed):

addTenWorkflow | wrun_01KPBXQ2P3RBRCDDEGEW5SPJ23 | 🔍 observability

express (1 failed):

resilient start: addTenWorkflow completes when run_created returns 500 | wrun_01KPBYDWAVQQN0JSJGKKZ7XWN6 | 🔍 observability

hono (1 failed):

outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_01KPBXYRJYF348HTDK2PTD0T88 | 🔍 observability

nextjs-webpack (1 failed):

outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns correct index after stream completes

nitro (2 failed):

DurableAgent e2e core single tool call
addTenWorkflow | wrun_01KPBXQ2P3RBRCDDEGEW5SPJ23 | 🔍 observability

nuxt (1 failed):

outputStreamWorkflow - getTailIndex and getChunks getChunks returns same content as reading the stream

sveltekit (1 failed):

sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_01KPBYD5PCQZEGQCZKQSM2DP8Z | 🔍 observability

vite (1 failed):

outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_01KPBXYRJYF348HTDK2PTD0T88 | 🔍 observability

🌍 Community Worlds (98 failed)

mongodb (15 failed):

readableStreamWorkflow | wrun_01KPBXQR3N3014MZMQ4YRFET90
hookWorkflow is not resumable via public webhook endpoint | wrun_01KPBXRVXV88DPETFNSE7WEP4T
webhookWorkflow | wrun_01KPBXS53RBMWNE9V7RKD36DTJ
outputStreamWorkflow no startIndex (reads all chunks)
outputStreamWorkflow positive startIndex (skips first chunk)
outputStreamWorkflow negative startIndex (reads from end)
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns correct index after stream completes
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns -1 before any chunks are written
outputStreamWorkflow - getTailIndex and getChunks getChunks returns same content as reading the stream
outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_01KPBXYRJYF348HTDK2PTD0T88
fetchWorkflow | wrun_01KPBY0KSEASX42VB22470AW3H
concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KPBY5TMRX9X604M40W2E4F7Y
health check (queue-based) - workflow and step endpoints respond to health check messages
health check (CLI) - workflow health command reports healthy endpoints
resilient start: addTenWorkflow completes when run_created returns 500 | wrun_01KPBYDWAVQQN0JSJGKKZ7XWN6

redis (15 failed):

readableStreamWorkflow | wrun_01KPBXQR3N3014MZMQ4YRFET90
hookWorkflow is not resumable via public webhook endpoint | wrun_01KPBXRVXV88DPETFNSE7WEP4T
webhookWorkflow | wrun_01KPBXS53RBMWNE9V7RKD36DTJ
outputStreamWorkflow no startIndex (reads all chunks)
outputStreamWorkflow positive startIndex (skips first chunk)
outputStreamWorkflow negative startIndex (reads from end)
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns correct index after stream completes
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns -1 before any chunks are written
outputStreamWorkflow - getTailIndex and getChunks getChunks returns same content as reading the stream
outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_01KPBXYRJYF348HTDK2PTD0T88
fetchWorkflow | wrun_01KPBY0KSEASX42VB22470AW3H
concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KPBY5TMRX9X604M40W2E4F7Y
health check (queue-based) - workflow and step endpoints respond to health check messages
health check (CLI) - workflow health command reports healthy endpoints
resilient start: addTenWorkflow completes when run_created returns 500 | wrun_01KPBYDWAVQQN0JSJGKKZ7XWN6

turso (68 failed):

addTenWorkflow | wrun_01KPBXQ2P3RBRCDDEGEW5SPJ23
addTenWorkflow | wrun_01KPBXQ2P3RBRCDDEGEW5SPJ23
wellKnownAgentWorkflow (.well-known/agent) | wrun_01KPBXSX8W2FN88Q5KBNQC236D
should work with react rendering in step
promiseAllWorkflow | wrun_01KPBXQAYBAB381RJM9BWP9GSA
promiseRaceWorkflow | wrun_01KPBXQKYSV98V7329SF011QD1
promiseAnyWorkflow | wrun_01KPBXQP1GV1T0YGJWSB6716N8
importedStepOnlyWorkflow | wrun_01KPBXT8ZHC15NBZFFAYDXQABA
readableStreamWorkflow | wrun_01KPBXQR3N3014MZMQ4YRFET90
hookWorkflow | wrun_01KPBXRFPZ91CN3EQA6QNSSYS8
hookWorkflow is not resumable via public webhook endpoint | wrun_01KPBXRVXV88DPETFNSE7WEP4T
webhookWorkflow | wrun_01KPBXS53RBMWNE9V7RKD36DTJ
sleepingWorkflow | wrun_01KPBXSDX3Y5VR9KG7HYR614FE
parallelSleepWorkflow | wrun_01KPBXT0ACCDABDMAGQ8XHGEC7
nullByteWorkflow | wrun_01KPBXT51EQS6VXPFY3VB4VT7E
workflowAndStepMetadataWorkflow | wrun_01KPBXT7342FS9YR158VN6ED1Z
outputStreamWorkflow no startIndex (reads all chunks)
outputStreamWorkflow positive startIndex (skips first chunk)
outputStreamWorkflow negative startIndex (reads from end)
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns correct index after stream completes
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns -1 before any chunks are written
outputStreamWorkflow - getTailIndex and getChunks getChunks returns same content as reading the stream
outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_01KPBXYRJYF348HTDK2PTD0T88
fetchWorkflow | wrun_01KPBY0KSEASX42VB22470AW3H
promiseRaceStressTestWorkflow | wrun_01KPBY0Q5X7JSPBNW0FYN78NBA
error handling error propagation workflow errors nested function calls preserve message and stack trace
error handling error propagation workflow errors cross-file imports preserve message and stack trace
error handling error propagation step errors basic step error preserves message and stack trace
error handling error propagation step errors cross-file step error preserves message and function names in stack
error handling retry behavior regular Error retries until success
error handling retry behavior FatalError fails immediately without retries
error handling retry behavior RetryableError respects custom retryAfter delay
error handling retry behavior maxRetries=0 disables retries
error handling catchability FatalError can be caught and detected with FatalError.is()
error handling not registered WorkflowNotRegisteredError fails the run when workflow does not exist
error handling not registered StepNotRegisteredError fails the step but workflow can catch it
error handling not registered StepNotRegisteredError fails the run when not caught in workflow
hookCleanupTestWorkflow - hook token reuse after workflow completion | wrun_01KPBY565BMDGP3ZX0D3YCNXCK
concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KPBY5TMRX9X604M40W2E4F7Y
hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running | wrun_01KPBY70AMK4K32QT05RHEST21
stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars) | wrun_01KPBY7M6G7XPGJT63FKT6HH1N
stepFunctionWithClosureWorkflow - step function with closure variables passed as argument | wrun_01KPBY7X5XE5A5D15HDYAGW82Z
closureVariableWorkflow - nested step functions with closure variables | wrun_01KPBY82P91Q3AWTYKS3KRY7N2
spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step | wrun_01KPBY84RXCAZ714Z9WRSGE82W
runClassSerializationWorkflow - Run instances serialize across workflow/step boundaries | wrun_01KPBY8G24NVKAPFEFTSME9X1H
health check (queue-based) - workflow and step endpoints respond to health check messages
health check (CLI) - workflow health command reports healthy endpoints
pathsAliasWorkflow - TypeScript path aliases resolve correctly | wrun_01KPBY8ZTSMTQV85Y2M146QXJK
Calculator.calculate - static workflow method using static step methods from another class | wrun_01KPBY95CRWV24KHEMDWG2TNE4
AllInOneService.processNumber - static workflow method using sibling static step methods | wrun_01KPBY9CW6F4Q36QD2XV07GKH4
ChainableService.processWithThis - static step methods using this to reference the class | wrun_01KPBY9KD19G4HH8P0X1Q7932J
thisSerializationWorkflow - step function invoked with .call() and .apply() | wrun_01KPBY9T60ESN4BKC4DHQ1B2XC
customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE | wrun_01KPBYA0TWSWDSK00NCXQC6V78
instanceMethodStepWorkflow - instance methods with "use step" directive | wrun_01KPBYAQT1342SRRZTYEH2MDPA
crossContextSerdeWorkflow - classes defined in step code are deserializable in workflow context | wrun_01KPBYB4AKKBQHCY6B27PJ78C0
stepFunctionAsStartArgWorkflow - step function reference passed as start() argument | wrun_01KPBYBMBA9B4CJDCQS0HA699C
cancelRun - cancelling a running workflow | wrun_01KPBYBVYZ2730CPDP65P0VG0E
cancelRun via CLI - cancelling a running workflow | wrun_01KPBYC54GF22YGX0EPJD16JJ9
pages router addTenWorkflow via pages router
pages router promiseAllWorkflow via pages router
pages router sleepingWorkflow via pages router
hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep | wrun_01KPBYCH3D2P57GXPPBYT1BHJZ
sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_01KPBYD5PCQZEGQCZKQSM2DP8Z
sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) | wrun_01KPBYDH84KCTJH4GT7WQATGMJ
importMetaUrlWorkflow - import.meta.url is available in step bundles | wrun_01KPBYDQXR9FCZJZQ84YPKATY0
metadataFromHelperWorkflow - getWorkflowMetadata/getStepMetadata work from module-level helper (#1577) | wrun_01KPBYDT2ZVMKY6D7658KPKDZD
resilient start: addTenWorkflow completes when run_created returns 500 | wrun_01KPBYDWAVQQN0JSJGKKZ7XWN6
getterStepWorkflow - getter functions with "use step" directive | wrun_01KPBYE0PFT48J3WVE2ENSST2W

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro	83	0	7
❌ example	82	1	7
❌ express	82	1	7
✅ fastify	83	0	7
❌ hono	82	1	7
✅ nextjs-turbopack	88	0	2
❌ nextjs-webpack	87	1	2
❌ nitro	81	2	7
❌ nuxt	82	1	7
❌ sveltekit	82	1	7
❌ vite	82	1	7

✅ 💻 Local Development

App	Passed	Skipped
✅ astro-stable	84	6
✅ express-stable	84	6
✅ fastify-stable	84	6
✅ hono-stable	84	6
✅ nextjs-turbopack-canary	71	19
✅ nextjs-turbopack-stable	90	0
✅ nextjs-webpack-canary	71	19
✅ nextjs-webpack-stable	90	0
✅ nitro-stable	84	6
✅ nuxt-stable	84	6
✅ sveltekit-stable	84	6
✅ vite-stable	84	6

✅ 📦 Local Production

App	Passed	Skipped
✅ astro-stable	84	6
✅ express-stable	84	6
✅ fastify-stable	84	6
✅ hono-stable	84	6
✅ nextjs-turbopack-canary	71	19
✅ nextjs-turbopack-stable	90	0
✅ nextjs-webpack-canary	71	19
✅ nextjs-webpack-stable	90	0
✅ nitro-stable	84	6
✅ nuxt-stable	84	6
✅ sveltekit-stable	84	6
✅ vite-stable	84	6

✅ 🐘 Local Postgres

App	Passed	Skipped
✅ astro-stable	84	6
✅ express-stable	84	6
✅ fastify-stable	84	6
✅ hono-stable	84	6
✅ nextjs-turbopack-canary	71	19
✅ nextjs-turbopack-stable	90	0
✅ nextjs-webpack-canary	71	19
✅ nextjs-webpack-stable	90	0
✅ nitro-stable	84	6
✅ nuxt-stable	84	6
✅ sveltekit-stable	84	6
✅ vite-stable	84	6

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack	90	0	0

❌ 🌍 Community Worlds

App	Passed	Failed
✅ mongodb-dev	6	0
❌ mongodb	56	15
✅ redis-dev	6	0
❌ redis	56	15
✅ turso-dev	6	0
❌ turso	3	68

✅ 📋 Other

App	Passed	Skipped
✅ e2e-local-dev-nest-stable	84	6
✅ e2e-local-postgres-nest-stable	84	6
✅ e2e-local-prod-nest-stable	84	6

📋 View full workflow run

❌ Some E2E test jobs failed:

Vercel Prod: failure
Local Dev: success
Local Prod: success
Local Postgres: success
Windows: success

Check the workflow run for details.

github-actions · 2026-04-16T19:52:15Z

📊 Benchmark Results

📈 Comparing against baseline from main branch. Green 🟢 = faster, Red 🔺 = slower.

workflow with no steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
💻 Local	🥇 Express	0.041s (-8.6% 🟢)	1.004s (~)	0.964s	10	1.00x
💻 Local	Nitro	0.044s (+2.3%)	1.005s (~)	0.961s	10	1.09x
🐘 Postgres	Express	0.055s (-5.5% 🟢)	1.011s (~)	0.956s	10	1.35x
🐘 Postgres	Nitro	0.059s (-37.9% 🟢)	1.009s (-3.2%)	0.950s	10	1.46x

workflow with 1 step

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
💻 Local	🥇 Express	1.127s (~)	2.006s (~)	0.879s	10	1.00x
💻 Local	Nitro	1.132s (~)	2.006s (~)	0.874s	10	1.00x
🐘 Postgres	Express	1.144s (~)	2.010s (~)	0.866s	10	1.01x
🐘 Postgres	Nitro	1.152s (+1.1%)	2.011s (~)	0.858s	10	1.02x

workflow with 10 sequential steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	10.872s (-0.8%)	11.021s (~)	0.149s	3	1.00x
🐘 Postgres	Nitro	10.889s (~)	11.022s (~)	0.134s	3	1.00x
💻 Local	Express	10.917s (~)	11.023s (~)	0.106s	3	1.00x
💻 Local	Nitro	10.919s (~)	11.022s (~)	0.103s	3	1.00x

workflow with 25 sequential steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Nitro	14.602s (~)	15.024s (~)	0.422s	4	1.00x
🐘 Postgres	Express	14.642s (~)	15.022s (~)	0.380s	4	1.00x
💻 Local	Nitro	14.964s (-0.7%)	15.028s (-6.3% 🟢)	0.064s	4	1.02x
💻 Local	Express	14.971s (~)	15.028s (~)	0.057s	4	1.03x

workflow with 50 sequential steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	14.030s (~)	14.739s (+1.0%)	0.709s	7	1.00x
🐘 Postgres	Nitro	14.204s (+1.7%)	15.024s (+5.0%)	0.820s	6	1.01x
💻 Local	Nitro	16.564s (-1.3%)	17.031s (~)	0.467s	6	1.18x
💻 Local	Express	16.605s (~)	17.031s (~)	0.425s	6	1.18x

Promise.all with 10 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	1.264s (~)	2.009s (~)	0.745s	15	1.00x
🐘 Postgres	Nitro	1.276s (~)	2.010s (~)	0.734s	15	1.01x
💻 Local	Nitro	1.512s (-7.3% 🟢)	2.007s (-3.2%)	0.495s	15	1.20x
💻 Local	Express	1.512s (+1.5%)	2.006s (~)	0.494s	15	1.20x

Promise.all with 25 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Nitro	2.341s (~)	3.010s (~)	0.669s	10	1.00x
🐘 Postgres	Express	2.346s (-0.6%)	3.011s (~)	0.664s	10	1.00x
💻 Local	Express	2.901s (-1.8%)	3.108s (-10.0% 🟢)	0.207s	10	1.24x
💻 Local	Nitro	3.104s (-1.2%)	4.009s (+3.2%)	0.905s	8	1.33x

Promise.all with 50 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	3.484s (~)	4.012s (~)	0.528s	8	1.00x
🐘 Postgres	Nitro	3.489s (~)	4.010s (~)	0.520s	8	1.00x
💻 Local	Nitro	8.219s (-1.6%)	8.772s (-2.8%)	0.554s	4	2.36x
💻 Local	Express	8.761s (+5.1% 🔺)	9.271s (+2.7%)	0.510s	4	2.51x

Promise.race with 10 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Nitro	1.258s (~)	2.009s (~)	0.751s	15	1.00x
🐘 Postgres	Express	1.265s (+0.6%)	2.010s (~)	0.745s	15	1.01x
💻 Local	Express	1.529s (-19.2% 🟢)	2.006s (-15.1% 🟢)	0.477s	15	1.22x
💻 Local	Nitro	1.542s (-17.4% 🟢)	2.006s (-14.3% 🟢)	0.464s	15	1.23x

Promise.race with 25 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Nitro	2.341s (~)	3.009s (~)	0.668s	10	1.00x
🐘 Postgres	Express	2.354s (+0.5%)	3.011s (~)	0.657s	10	1.01x
💻 Local	Nitro	2.821s (-8.0% 🟢)	3.454s (-11.1% 🟢)	0.633s	9	1.21x
💻 Local	Express	2.994s (-4.4%)	3.760s (~)	0.766s	8	1.28x

Promise.race with 50 concurrent steps

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	3.470s (-0.8%)	4.011s (~)	0.541s	8	1.00x
🐘 Postgres	Nitro	3.517s (+1.1%)	4.016s (~)	0.499s	8	1.01x
💻 Local	Nitro	8.470s (-7.4% 🟢)	9.023s (-10.0% 🟢)	0.552s	4	2.44x
💻 Local	Express	9.066s (+3.0%)	9.775s (+5.4% 🔺)	0.710s	4	2.61x

workflow with 10 sequential data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.828s (-1.4%)	1.023s (~)	0.196s	59	1.00x
🐘 Postgres	Nitro	0.851s (+3.7%)	1.024s (+1.7%)	0.173s	59	1.03x
💻 Local	Nitro	0.992s (+1.2%)	1.229s (+12.4% 🔺)	0.237s	49	1.20x
💻 Local	Express	0.992s (+0.8%)	1.249s (+16.1% 🔺)	0.257s	49	1.20x

workflow with 25 sequential data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	1.979s (~)	2.316s (+2.6%)	0.337s	39	1.00x
🐘 Postgres	Nitro	2.085s (+8.2% 🔺)	2.686s (+27.9% 🔺)	0.601s	34	1.05x
💻 Local	Nitro	3.009s (-0.9%)	3.585s (-4.6%)	0.576s	26	1.52x
💻 Local	Express	3.045s (+1.0%)	3.609s (+0.7%)	0.564s	25	1.54x

workflow with 50 sequential data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	3.998s (~)	4.492s (+2.8%)	0.494s	27	1.00x
🐘 Postgres	Nitro	4.107s (~)	4.852s (+5.4% 🔺)	0.745s	25	1.03x
💻 Local	Nitro	9.099s (-2.1%)	9.787s (-2.3%)	0.688s	13	2.28x
💻 Local	Express	9.179s (~)	9.864s (-1.5%)	0.685s	13	2.30x

workflow with 10 concurrent data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.285s (+1.0%)	1.007s (~)	0.722s	60	1.00x
🐘 Postgres	Nitro	0.291s (+2.9%)	1.007s (~)	0.716s	60	1.02x
💻 Local	Express	0.568s (+1.4%)	1.004s (~)	0.436s	60	1.99x
💻 Local	Nitro	0.571s (-5.6% 🟢)	1.004s (-1.7%)	0.434s	60	2.00x

workflow with 25 concurrent data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.500s (-1.9%)	1.007s (~)	0.507s	90	1.00x
🐘 Postgres	Nitro	0.517s (+4.2%)	1.007s (~)	0.490s	90	1.03x
💻 Local	Nitro	2.486s (-2.0%)	3.008s (~)	0.522s	30	4.97x
💻 Local	Express	2.512s (~)	3.008s (~)	0.496s	30	5.02x

workflow with 50 concurrent data payload steps (10KB)

💻 Local Development

World	Framework	Workflow Time	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.814s (-0.6%)	1.009s (-0.8%)	0.196s	119	1.00x
🐘 Postgres	Nitro	0.837s (+6.0% 🔺)	1.019s (+1.2%)	0.182s	118	1.03x
💻 Local	Nitro	10.974s (-1.9%)	11.573s (-0.8%)	0.599s	11	13.49x
💻 Local	Express	11.161s (~)	11.666s (-2.3%)	0.505s	11	13.71x

Stream Benchmarks (includes TTFB metrics)

workflow with stream

💻 Local Development

World	Framework	Workflow Time	TTFB	Slurp	Wall Time	Overhead	Samples	vs Fastest
💻 Local	🥇 Nitro	0.203s (-5.0% 🟢)	1.004s (~)	0.012s (-6.4% 🟢)	1.018s (~)	0.815s	10	1.00x
💻 Local	Express	0.204s (+2.5%)	1.004s (~)	0.012s (-4.1%)	1.018s (~)	0.814s	10	1.00x
🐘 Postgres	Nitro	0.222s (+8.4% 🔺)	0.996s (~)	0.002s (+6.7% 🔺)	1.012s (~)	0.790s	10	1.10x
🐘 Postgres	Express	0.230s (+12.0% 🔺)	0.997s (~)	0.001s (-18.8% 🟢)	1.011s (~)	0.781s	10	1.13x

stream pipeline with 5 transform steps (1MB)

💻 Local Development

World	Framework	Workflow Time	TTFB	Slurp	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.632s (~)	1.006s (~)	0.018s (+362.4% 🔺)	1.036s (+1.3%)	0.404s	59	1.00x
🐘 Postgres	Nitro	0.635s (+1.7%)	1.005s (~)	0.004s (+5.3% 🔺)	1.023s (~)	0.389s	59	1.00x
💻 Local	Express	0.747s (-1.4%)	1.012s (-1.7%)	0.009s (+0.6%)	1.023s (-1.6%)	0.276s	59	1.18x
💻 Local	Nitro	0.947s (+12.9% 🔺)	1.011s (~)	0.010s (+1.7%)	1.227s (+9.9% 🔺)	0.280s	49	1.50x

10 parallel streams (1MB each)

💻 Local Development

World	Framework	Workflow Time	TTFB	Slurp	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	0.969s (+0.8%)	1.192s (-6.7% 🟢)	0.000s (+35.3% 🔺)	1.204s (-7.8% 🟢)	0.235s	51	1.00x
🐘 Postgres	Nitro	1.002s (+3.4%)	1.359s (+8.9% 🔺)	0.000s (-45.5% 🟢)	1.379s (+9.7% 🔺)	0.378s	44	1.03x
💻 Local	Nitro	1.210s (-1.0%)	2.019s (~)	0.000s (+233.3% 🔺)	2.021s (~)	0.810s	30	1.25x
💻 Local	Express	1.239s (+1.2%)	2.022s (~)	0.001s (+80.0% 🔺)	2.024s (~)	0.784s	30	1.28x

fan-out fan-in 10 streams (1MB each)

💻 Local Development

World	Framework	Workflow Time	TTFB	Slurp	Wall Time	Overhead	Samples	vs Fastest
🐘 Postgres	🥇 Express	1.855s (+4.7%)	2.249s (+3.3%)	0.000s (+Infinity% 🔺)	2.267s (+3.1%)	0.413s	28	1.00x
🐘 Postgres	Nitro	1.930s (+7.7% 🔺)	2.309s (+7.8% 🔺)	0.000s (+7.7% 🔺)	2.319s (+6.6% 🔺)	0.389s	26	1.04x
💻 Local	Express	3.432s (-1.0%)	4.033s (~)	0.001s (-8.3% 🟢)	4.035s (~)	0.603s	15	1.85x
💻 Local	Nitro	3.457s (+2.1%)	4.099s (+1.7%)	0.000s (-50.0% 🟢)	4.102s (+1.6%)	0.644s	15	1.86x

Summary

Fastest Framework by World

Winner determined by most benchmark wins

World	🥇 Fastest Framework	Wins
💻 Local	Nitro	13/21
🐘 Postgres	Express	16/21

Fastest World by Framework

Winner determined by most benchmark wins

Framework	🥇 Fastest World	Wins
Express	🐘 Postgres	18/21
Nitro	🐘 Postgres	18/21

Column Definitions

Workflow Time: Runtime reported by workflow (completedAt - createdAt) - primary metric
TTFB: Time to First Byte - time from workflow start until first stream byte received (stream benchmarks only)
Slurp: Time from first byte to complete stream consumption (stream benchmarks only)
Wall Time: Total testbench time (trigger workflow + poll for result)
Overhead: Testbench overhead (Wall Time - Workflow Time)
Samples: Number of benchmark iterations run
vs Fastest: How much slower compared to the fastest configuration for this benchmark

Worlds:

💻 Local: In-memory filesystem world (local development)
🐘 Postgres: PostgreSQL database world (local development)
▲ Vercel: Vercel production/preview deployment
🌐 Turso: Community world (local development)
🌐 MongoDB: Community world (local development)
🌐 Redis: Community world (local development)
🌐 Jazz: Community world (local development)

📋 View full workflow run

⚠️ Community world benchmarks failed (non-blocking):

Community Worlds: failure

Check the workflow run for details.

VaguelySerious requested a review from a team as a code owner April 16, 2026 19:52

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VaguelySerious added the backport-stable Cherry-pick this PR to the stable branch when merged label Apr 16, 2026

VaguelySerious closed this Apr 16, 2026

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VaguelySerious commented Apr 16, 2026

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🧪 E2E Test Results

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📊 Benchmark Results

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