BadGateway status code 502 running Excel Online Office script with 7800 csv records.

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Posted on by FG-27031939-0

I am running a power automate cloud flow. The action (Run Office Script) from Excel online is failing (bad gateway) when trying to run an office script that uses to convert CSV data into an excel table.

When execution with just a few records from the csv file (100 records) to action finishes fine. But I am now trying the full load of csv records that need to be converted, which is about 7,820 records.

I downloaded the Action input to verify, and it seems it has all the data needed, which in JSON format is about 11,077kb in size.

The action output error is the following:

"body": {

"error": {

"code": 502,

"source": "flow-apim-unitedstates-002-eastus-01.azure-apim.net",

"clientRequestId": "419dfdbf-09df-401b-9030-7e7b05cc26ce",

"message": "BadGateway",

"innerError": {

"StatusCode": 500,

"Message": "Oops! Something went wrong.\r\nclientRequestId: 419dfdbf-09df-401b-9030-7e7b05cc26ce",

"RequestId": "419dfdbf-09df-401b-9030-7e7b05cc26ce"

}

Is this error because of the large size of data that needs to be processed? Can I adjust any configuration to increase processing capacity?

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11manish 943 on at

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In Microsoft Power Automate, your Run Office Script (Excel Online) action works for small data (~100 rows) but fails with:

❌ 502 BadGateway / 500 internal error

when processing ~7,820 rows (~11 MB JSON payload).

Root Cause

Yes — this is very likely due to size & execution limits

Key constraints in Microsoft Excel Online + Office Scripts:

Payload size limits (request/response)

Script execution time limits (~2–5 minutes)

Memory constraints inside Office Scripts

Connector throttling / API gateway limits

Your 11 MB JSON + transformation logic is exceeding one or more of these limits.

Important

You CANNOT increase capacity/config limits for:

Office Script runtime

Excel Online connector

Power Automate action timeout (for this connector)

Recommended Solutions (Best Practices)

Split Data into Chunks (Most Recommended)

Instead of sending 7,800 rows at once:

Break into smaller batches (e.g., 500–1000 rows)

Flow pattern:

CSV → Parse → Split array → Apply to each (batch)
↓
Run Office Script per batch

Avoids timeout

Prevents payload overflow

Avoid Passing Large JSON to Script

Instead of:

Flow → pass full JSON → script processes

Do this:

Store CSV in OneDrive/SharePoint

Let script read file directly

✔ Reduces payload size
✔ Improves performance

Thanks
Manish

Visit my blog : https://powerappbuilder.blogspot.com/

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Valantis 2,651 on at

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Hi @FG-27031939-0,

it’s platform limits. there’s nothing you can “turn up.”

try this:

Resave the workbook as standard .xlsx (not “Strict Open XML”). This specific format causes BadGateway with Run script.

Batch your writes in the Office Script (e.g., ~1,000 cells per batch) instead of one large setValues. Use the “Write a large dataset” pattern.

If it still runs >120 seconds, split the flow to call Run script in a loop over CSV chunks (each under the 5 MB per-call workbook interaction and <120 s). Your ~11 MB input is below the 30 MB Run script parameter cap; the bottlenecks are the 5 MB Excel call limit and the 120 s timeout.

Validate

Rerun the flow; confirm no 502 and that all 7,820 rows are written in batches within ~120 s per run.

Sources

Platform limits (5 MB per call, 120 s timeout, 30 MB parameter limit, ISO strict not supported): https://learn.microsoft.com/office/dev/scripts/testing/platform-limits#data-limits and https://learn.microsoft.com/office/dev/scripts/testing/platform-limits#power-automate-specific-restrictions

Batch pattern (with Power Automate loop): https://learn.microsoft.com/office/dev/scripts/resources/samples/write-large-dataset

Power Automate timeouts: https://learn.microsoft.com/power-automate/limits-and-config#timeout

Best regards,

Valantis

✅ If this helped solve your issue, please Accept as Solution so others can find it quickly.

❤️ If it didn’t fully solve it but was still useful, please click “Yes” on “Was this reply helpful?” or leave a Like :).

🏷️ For follow-ups @Valantis.

📝 https://valantisond365.com/

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Valantis 2,651 on at

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Hi @FG-27031939-0,

Just wanted to check in and see if everything is working now. If you still need any help, feel free to let me know.

Also, if the issue is resolved, it would be great if you could mark the answer as solved so others with the same question can find it easily.

Thanks and have a great day!

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