Simple Function validator appears to reject NodeJS bundles above ~64 KiB

Developer API & SDK
1

I’m developing a private ServiceM8 Simple Function Add-on called Report Connect using:

  • @servicem8/addon-kit 1.0.1
  • Node 24.14.0
  • Addon Kit/esbuild output using:
    • platform: node
    • target: node24
    • format: cjs

Local Addon Kit validation and deploy --dry-run pass successfully.

However, ServiceM8’s server-side validator rejects some deployed functions with:

Function validation failed - check for syntax errors: {"success":false}

I isolated this using several deliberately separate diagnostic bundles:

Passing

  • 1.2 KB minimal documented handler
    Deployment: 01a08d14-2adb-78d3-9fc9-894a992aae7b
  • 43.5 KB generated-assets-only diagnostic handler
    Deployment: 01a08d19-8ea6-78d3-9fc8-bbb7e26f1d3b

Failing

  • 71.6 KB UI/mock/assets diagnostic bundle
    Deployment: 01a08d16-8ddd-78d3-9fc8-51a5db66a39b
  • 82.0 KB authentication/direct-engine diagnostic bundle
    Deployment: 01a08d15-71f2-78d3-9fc9-b09abe8fda0b
  • 162.5 KB full Report Connect bundle
    Deployment: 01a08d0c-c921-78d3-9fc8-ca4d58d1292b

The two failing diagnostic bundles contain substantially different code, while both smaller bundles pass. This appears to put the validator boundary somewhere between roughly 43.5 KB and 71.6 KB, with ~64 KiB being a possible threshold, although I have not proven the exact value.

The full generated CommonJS bundle:

  • passes Node 24 syntax checking locally;
  • exports a callable named handler;
  • returns { eventResponse };
  • executes successfully locally;
  • passes Addon Kit dry-run.

No manual minification was used for these deployed diagnostic probes; they were packaged through Addon Kit 1.0.1 using its normal bundling path.

The current Addon Kit documentation refers to a much larger bundle limit, so I’m trying to understand whether there is a separate undocumented server-side function-validation size limit.

Could anyone confirm:

  1. Is there a separate maximum function size enforced by the Simple Function validator?
  2. If so, what is the actual limit?
  3. Is there any additional validator output available for the failed deployment IDs above?
  4. Is there a recommended bundling/minification approach for NodeJS Add-ons near this threshold?

Minimal reproducible example

A minimal handler such as:



export async function handler() {
  return {
    eventResponse: "<html><body>Validator test</body></html>"
  };
}

deploys successfully at approximately 1.2 KB. Increasing the bundled function through unrelated imports eventually causes the opaque validator failure described above.

No credentials or customer data are involved in the diagnostic deployments.

Thanks,
Kim

2

Hi Kim, thanks for the detailed report. I’ve notified the team, and they’re investigating the validator behaviour you’ve described. We’ll share an update here when we have more information.

Thanks,
Cody

3

Hi Kim, this issue has now been resolved and the fix is live. We’ve verified that a 174.6 KiB bundle using modern Node 24 JavaScript deploys successfully through Addon Kit.

Please retry your deployment. If you still see an error, share the new deployment ID here and we’ll take another look.

Thanks for the detailed report—it helped us track this down.

Cody

4

Hi

Great news thanks, we will rety the deployment, and thank you for our speedy response.

Kind regards
Kim

5

Hi Cody,

Thanks again for getting the validator issue fixed.

I’ve now retried deployment of the genuine Report Connect bundle.

The previous Function validation failed error no longer occurs, so the validator fix appears to be working.

The 162.5 KiB bundle was uploaded and accepted, but the deployment then failed later in the pipeline with:

Deployment pipeline error - check platform logs

New deployment ID:

01a091a4-2da5-78d3-9fc9-c41b7a219bdb

Local checks remain green:

  • Node 24 / Addon Kit 1.0.1
  • 23/23 tests passed
  • Addon Kit dry-run passed
  • bundle size 166,359 bytes / 162.5 KiB
  • manifest/schema validation passed

No code changes were made after the previous diagnostics.

Would you be able to check the platform logs for that deployment ID and let me know what stage is now failing?

Thanks again,
Kim

6

Hi Kim,

Thanks for sharing the new deployment ID, and sorry for the additional trouble.

We traced this error to a separate platform-side issue that selected an outdated validator. We’ve also tested your exact uploaded bundle against the updated validator, and it passes.

Could you please try deploying again? No code changes should be needed for this issue. If it still fails, please share the new deployment ID and error message so we can follow it through.

Thanks,
Cody

7

Hi Cody

Thanks again for your prompt response.

Kind regards
Kim

8

Hi Cody,

Thanks again for your help.

Report Connect is now activated and switched ON in the East Kent ServiceM8 account, but no Report Connect item appears under the web Add-ons menu.

We’ve checked the current manifest and handler again and can’t find a configuration mismatch.

The menu item is:

name: "Report Connect"
type: "addon"
event: "report_connect_open"

The icon URL is valid and returns HTTP 200 image/png, Addon Kit 1.0.1 validates the manifest, and the handler matches the exact same lowercase event name.

Could you please check:

  1. Whether deployment 01a0940f-8bcb-78d3-9fc8-684f6c797cab reached a terminal deployed state;
  2. What effective manifest is currently attached to the installed report-connect Add-on;
  3. Whether that manifest contains the menuItems entry above;
  4. Whether the East Kent activation generated the corresponding web Add-ons menu registration.

The Add-on itself is visible under Settings → ServiceM8 Add-ons → Custom Addons and is switched ON.

Thanks,
Kim

9

Hi Cody,

Ignore me, I’ve found it!

Too set in my ways where I expected it to be.

Kind regards
Kim

10

Hi Kim,

Good to hear the original validator failure is no longer occurring on your retry.

The new Deployment pipeline error - check platform logs message needs platform-side log review before we can confirm the failing stage or cause.

Simple Function Add-ons run on ServiceM8-managed infrastructure, so we’ll treat this as a platform-side follow-up against deployment ID 01a091a4-2da5-78d3-9fc9-c41b7a219bdb.

We’ll update this thread once the log review is complete.

Thanks,
Cody