Resumable uploads on the web: past, present and future

File uploads are a ubiquitous and fundamental part of modern web applications. While simple at first, they become increasingly challenging as file sizes grow. Users expect reliable data transfers, even when uploading multi-gigabyte files over unreliable mobile networks.

Conventional file uploads over HTTP fail unrecoverably when the underlying connection is interrupted. Resumable uploads, on the other hand, allow an application to continue uploading a file exactly where it left off. This preserves previously transferred data and greatly improves the user experience.

Historically, resumable uploads were implemented in proprietary ways, with each application building its own solution. Developers couldn’t benefit from the advantages of resumable uploads without investing significant engineering effort.

In 2013, we started the tus project and created a free and open-source protocol for resumable uploads. The project and its community provide implementations for various client and server runtimes, making it easy today to add resumable uploads to any application.

In 2022, we began engaging with the HTTP Working Group at the IETF to make resumable uploads a standardized extension to HTTP. Our goal is to integrate resumable uploads directly into browsers, HTTP clients, servers, and proxies so that even more developers can easily benefit from their capabilities.

This talk explores the past and present of resumable uploads and how upcoming standards will help developers deliver exceptional file-upload experiences.

Additional links: - Tus homepage: https://tus.io/ - GitHub organization: https://github.com/tus - “Resumable Uploads for HTTP” Internet-Draft: https://datatracker.ietf.org/doc/draft-ietf-httpbis-resumable-upload/