# SignatureDoesNotMatch on S3 presigned URLs from local\_upload (V4 API)

**URL:** <https://forum.frame.io/t/signaturedoesnotmatch-on-s3-presigned-urls-from-local-upload-v4-api/3812>\
**Category:** Help\
**Tags:** api, v4\
**Created:** [October 1, 2026, 2:40pm UTC](https://forum.frame.io/t/signaturedoesnotmatch-on-s3-presigned-urls-from-local-upload-v4-api/3812 "2026-10-01T14:40:37Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![baptistevisuals](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@baptistevisuals](https://forum.frame.io/u/baptistevisuals)\
**Post date:** [October 1, 2026, 2:40pm UTC](https://forum.frame.io/t/signaturedoesnotmatch-on-s3-presigned-urls-from-local-upload-v4-api/3812/1 "2026-10-01T14:40:37Z")

</div>

Hi all,

I’m building an integration with the [Frame.io](http://Frame.io) V4 API (OAuth Web App / Adobe IMS auth). Everything works fine up to file upload:

1. `POST /v4/accounts/{account_id}/folders/{folder_id}/files/local_upload` with `{name, file_size}` → succeeds, returns `upload_urls` with one or more presigned S3 URLs.
2. `PUT` the file bytes to that presigned URL → fails every time with AWS `SignatureDoesNotMatch`, even when strictly matching the `SignedHeaders` required by the signature (`content-type`, `host`, `x-amz-acl`, sent empty as the canonical request demands).

I isolated this with a clean `curl` request completely outside my app, reproducing the exact headers required by the signature — same error. Also reproduced via a real browser upload (multi-part, 11 parts). This suggests the presigned signature returned by the API doesn’t validate against AWS regardless of how the client constructs the request.

[Frame.io](http://Frame.io) support confirmed my Adobe ID / API auth is correctly set up and pointed me here since this is API-specific.

A few `RequestId`s from the AWS error responses, for reference:

- `1SDVH32MHDMJK9M0`
- `XXV95SF2JF8ZZV8F`
- `PKK895VEYZH3K1ZP`

Has anyone else hit this on `local_upload`, or found a workaround? Happy to share more details (minus account-specific info) if useful.

Thanks!

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