topic Re: Could not determine name from file in APIs & Integrations

Could not determine name from file

PieterVHeerden — Tue, 23 May 2023 11:14:13 GMT

Hi all,

I am using the following API to upload a file using postman

/files/v3/files

I am using this as my guideline : https://developers.hubspot.com/docs/api/files/files

When i select a file, it creates the file in CRM

When i change the file paramater to text (and add my base64 string), i get the above error.

Even if i add the fileName paramater, it says the same thing.

Any help would be appreciated. I know it is something very small

Thanks

Re: Could not determine name from file

Jaycee_Lewis — Wed, 24 May 2023 17:58:48 GMT

Hey, @PieterVHeerden 👋 Thanks for your question!

I don't see an error message in your post. Can you add it here as a reply? Pasting it in and using the code block tool is best, as extracting the error messages and searching with them is hard with from just a screenshot.

I have a few questions:
Could you please provide the full error message you're encountering? This can often give us more insight into what's going wrong.
Can you share a sample of your request, including the URL, headers, and body, along with the response you receive? You can just copy and paste this from Postman. Please remember to exclude any sensitive information.
Are you confident that your base64 string is a valid representation of the file you're trying to upload? Mis-formatted or corrupted base64 strings can cause issues when uploading files.

Thank you! — Jaycee

Re: Could not determine name from file

PieterVHeerden — Thu, 25 May 2023 05:18:22 GMT

Hi Jaycee,

Please see below. If i upload a file in postman it works. once I change file to be text in the body, that is when it fails. If i add fileName in the body, this yields the same error

Could you please provide the full error message you're encountering? This can often give us more insight into what's going wrong.
- {
      "status": "error",
      "message": "Could not determine name from file",
      "correlationId": "3460cb4a-1540-403d-99af-5cad3692bcfa",
      "category": "BAD_REQUEST"
  }
Can you share a sample of your request, including the URL, headers, and body, along with the response you receive? You can just copy and paste this from Postman. Please remember to exclude any sensitive information.
- Params = nothing
- POST
- {{baseUrl}}/files/v3/files
- Auth = Bearer Token
- Body
  - Form Data
  - file = <== add your own base64 string
  - folderPAth = /
  - options
    - {"access":"PRIVATE","overwrite":false,"duplicateValidationStrategy":"NONE","duplicateValidationScope":"ENTIRE_PORTAL"}
Are you confident that your base64 string is a valid representation of the file you're trying to upload? Mis-formatted or corrupted base64 strings can cause issues when uploading files <== Yes if i take the same sting in C# then it uploads

Thanks

Re: Could not determine name from file

jeff00seattle — Sun, 04 Jun 2023 12:31:56 GMT

Any luck?

I am experiencing the same issue.

Re: Could not determine name from file

AKemeklis — Mon, 28 Aug 2023 19:36:16 GMT

Hey,

I am also having the same issue.

I am passing a Base64 encored file (this is the only part I am not fully sure of).

But other than that, everything is according to the docs. I run plenty of API calls through Hubspot with the same authentication so I assume that's not the problem either.

is there any way we can get help?

Re: Could not determine name from file

MWeber7 — Fri, 19 Dec 2025 15:54:41 GMT

Any update on this? Experiencing the same problem

Re: Could not determine name from file

Victor_Becerra — Fri, 19 Dec 2025 22:06:17 GMT

Hi @MWeber7

Thank you all for reaching out to the Community and sharing the details of your experience with the file upload endpoint — it definitely helps to see multiple users encountering the same behavior.

I'd like to invite some of our community members who are subject matter experts to join this conversation: Hey @SteveHTM @RubenBurdin @d-lupo Happy Friday! Would you be able to share any insights on uploading Base64-encoded files via /files/v3/files and the “Could not determine name from file” error? Your expertise would be greatly appreciated.

Best,
Victor

Re: Could not determine name from file

Victor_Becerra — Mon, 19 Jan 2026 15:12:51 GMT

Hi everyone, thanks to all of you for the details you’ve shared so far.

That Could not determine name from file error is coming from how the multipart body is built. When file is sent as a text field with a base64 string (instead of a real file upload), the part doesn’t have a filename, so /files/v3/files can’t infer one and returns this error. The fix is to send file as an actual file part with a filename (or decode your base64 to bytes and append it as the file field with something like my-document.pdf as the filename), and keep options and folderPath as separate form fields. You don’t need a separate fileName field; the API reads the filename from the file part itself.

You can see the expected multipart/form-data shape in our Files API docs here: https://developers.hubspot.com/docs/api/files/files.

Hope it helps!
Best, Victor