What is delta-cli?

Delta CLI is a command line tool for publishing over-the-air updates to React Native apps. Instead of sending users a full new copy of the app's JavaScript bundle every time something changes, Delta computes a binary patch that contains only the difference between the old and new version, then delivers just that patch. This makes updates smaller to download, faster to roll out, and lighter on a user's data usage compared to tools that replace the whole bundle each time. The CLI is the developer-facing part of a larger Delta platform. Two companion projects handle the other pieces: a React Native SDK that receives and applies the patches inside the app, and a backend server that stores releases and serves the update API. Delta CLI itself is what a developer or a CI pipeline runs to package a release, generate the patch, and publish it. With the CLI a developer can build a production bundle from their React Native project, generate a binary patch against a previous release, and publish that update to a Delta server with a single command. It also handles managing releases across different environments and release channels, tracking release history and metadata, and authenticating securely with the Delta server. Configuration lives in a delta.config.json file in the project, which points the CLI at the AWS S3 bucket and Lambda functions that back the Delta service, since the platform runs on AWS infrastructure. Because it is built to slot into automated workflows, Delta CLI is designed to run inside CI and CD pipelines such as GitHub Actions, Bitrise, CircleCI, Codemagic, Azure DevOps, or Jenkins, so a team can ship hotfixes or small feature updates without waiting on an app store review each time. This tool is aimed at React Native developers and mobile teams who want to ship bug fixes and small updates quickly, and who are comfortable setting up their own AWS backend to host the Delta service.