What you'll find here
The File API and Blob objects, multipart/form-data on the wire, the Fetch and Streams APIs, base64 vs binary trade-offs, magic-byte type detection, timeout and retry logic, and the size ceilings between the browser and your handler.
Explore section →S3 presigned URL workflows, server-side validation with libmagic, ClamAV and quarantine buckets, direct-to-cloud patterns across S3, GCS and Azure Blob, post-upload transcoding, metadata indexing, lifecycle rules, and abuse protection.
Explore section →Resumable upload state machines, real-time progress over WebSockets and SSE, error-recovery patterns with exponential backoff, and client-side media preprocessing that shrinks a 12 MB photo before it ever leaves the device.
Explore section →Start here
The four pages most people need first, whichever end of the pipeline they are working on.
IAM scoping, TypeScript implementation, CORS configuration, and ETag verification for direct S3 uploads.
Read article →What a multipart body actually looks like on the wire — boundaries, part headers, and the bytes in between.
Read topic →When one request beats chunking on latency and complexity — and when finer retry granularity wins.
Read article →The states a real upload moves through, and how to persist them so a dropped connection costs seconds, not megabytes.
Read topic →Newest in the library
The latest additions go past the happy path — streaming request bodies, transcoding pipelines, abuse protection, and preprocessing media in the browser.
ReadableStream request bodies, duplex: "half", and flat memory use on files of any size.
Read topic →Event-driven derivative pipelines with FFmpeg, Sharp, and a queue that survives a poison message.
Read topic →Token buckets on URL issuance, POST-policy size limits S3 itself enforces, and zip-bomb defence.
Read topic →Canvas and WebCodecs resizing, EXIF stripping, and the privacy case for doing it before upload.
Read topic →Why File.type is a guess, how to read magic bytes, and what the accept attribute really does.
Read topic →