# 500 Internal Server Error on POST https://api.pdfjs.express/xfdf/merge

**URL:** <https://pdfjs.community/t/500-internal-server-error-on-post-https-api-pdfjs-express-xfdf-merge/3352>\
**Category:** Bug Reports\
**Tags:** pdfjs-express\
**Created:** [July 11, 2024, 10:13pm UTC](https://pdfjs.community/t/500-internal-server-error-on-post-https-api-pdfjs-express-xfdf-merge/3352 "2024-07-11T22:13:47Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![devops1](https://avatars.discourse-cdn.com/v4/letter/d/0ea827/32.png) [@devops1](https://pdfjs.community/u/devops1)\
**Post date:** [July 11, 2024, 10:13pm UTC](https://pdfjs.community/t/500-internal-server-error-on-post-https-api-pdfjs-express-xfdf-merge/3352/1 "2024-07-11T22:13:47Z")

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**Description:**  
We are encountering a 500 Internal Server Error when making a POST request to the following endpoint:

**Endpoint:** [https://api.pdfjs.express/xfdf/merge](https://api.pdfjs.express/xfdf/merge)  
**HTTP Method:** POST

**Additional details:**

- The error started occurring recently (July 11, 2024 9.43 PM UTC)
- This endpoint was previously working as expected
- No changes were made to our implementation before the error started occurring

Steps to reproduce:

1. Send a POST request to [https://api.pdfjs.express/xfdf/merge](https://api.pdfjs.express/xfdf/merge)
2. Observe the 500 Internal Server Error response

Expected behavior:  
The API should process the request and return a successful response.

Actual behavior:  
The API returns a 500 Internal Server Error.

Impact:  
This issue is preventing us from merging XFDF data, which is critical for our application’s functionality.

 ![image](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/2X/9/9b932cf36f70d340ea04a10785d16cb98715cfdd.png)  
 ![Screenshot 2024-07-11 at 15.18.43](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/2X/b/b86851f96d8cfceb3135a18b9b474a703407c33e.png)  
 ![Screenshot 2024-07-11 at 15.19.26](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/2X/5/556d19d9e6455e13d41e564ce8a64891167976a5.png)

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<div class="post-metadata">

**Author:** ![kkim](https://avatars.discourse-cdn.com/v4/letter/k/3ab097/32.png) [@kkim](https://pdfjs.community/u/kkim)\
**Post date:** [August 9, 2024, 9:06pm UTC](https://pdfjs.community/t/500-internal-server-error-on-post-https-api-pdfjs-express-xfdf-merge/3352/3 "2024-08-09T21:06:59Z")

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Hi there,

It looks like you are getting error code 27, which indicates that a client side key was provided for a server side request:

> **[PDF.js Express API Errors | Documentation](https://pdfjs.express/documentation/utils/errors#errors)**

Could you verify if the key was passed correctly on your end?

Best regards,  
Kevin Kim