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#presigned-url

2 stories

Banner: a large file split into numbered parts uploading in parallel from a browser to object storage

Web Development

Uploading 10 GB files to S3 from the browser: presigned multipart with resume

John Nguyen · May 23, 2025 · 10 min read

Video and dataset uploads of 5 to 15 GB kept failing through our API servers. We moved to browser-direct S3 multipart uploads with per-part presigned URLs, resumable state, per-part checksums and server-side completion. This is the full design and working code.

Banner: a browser upload to an S3 presigned URL rejected because the signed and sent headers differ

Cloud & Infrastructure Bug Report

S3 presigned PUT upload fails with SignatureDoesNotMatch from the browser

Daniel Tran · Apr 8, 2025 · 9 min read

Receipt uploads to S3 failed with 403 SignatureDoesNotMatch for about 4 percent of users, mostly iPhone photos uploaded from Windows. The URL was signed with one Content-Type and the browser sent another. Reading the CanonicalRequest in the error pinpointed it.