## TL;DR

1) Line endings: literal backslash-r-backslash-n sequences in the ColdFusion source were sent as-is; replacing them with chr(13) and chr(10) produced real CRLF bytes. 2) The GraphQL mutation text did not match the documented add_file_to_column shape; reformatting the query per the docs fixed the server-side parse. Three issues were breaking the upload.

## Fix

1. 1) Line endings: literal backslash-r-backslash-n sequences in the ColdFusion source were sent as-is; replacing them with chr(13) and chr(10) produced real CRLF bytes.
   Expected: You get the expected result; the problem is gone.
2. 2) The GraphQL mutation text did not match the documented add_file_to_column shape; reformatting the query per the docs fixed the server-side parse.
   Expected: You get the expected result; the problem is gone.

## When to use

- You are dealing with this situation.
- The symptom matches: Problem adding files with ColdFusion via Monday.com API.

## When NOT to use

- Unrelated issues with a different cause.
- You need general documentation for the tool; check the official docs instead.

## Compatibility

Reported per the linked source.

## Variant phrasings

### Problem adding files with ColdFusion via Monday.com API

## Why it happens

Stack Overflow #71641641 (accepted answer, 4 votes): uploading a file to the Monday API from ColdFusion. The asker had items, updates, columns, boards, and reads working, but file upload kept failing. They were porting a NodeJS multipart-upload example ('Uploading a file to monday.com, the hard way') to ColdFusion and building the multipart body by hand with string concatenation.

## Edge cases

- If your error message differs even slightly, this is probably a different issue; search the exact text.
- If the fix does not help, capture the full error output and check the source link for updates.