Cloudflare R2 is an object storage service made by Cloudflare, Inc. Object storage keeps files (objects) such as images, videos, backups and datasets in containers called buckets, where each file is found by a key, instead of in the file system of one server. R2 runs on the same infrastructure that Cloudflare uses for its own services.
R2 offers an S3-compatible API, the same interface as Amazon S3 storage, so existing tools and SDKs work after a change of endpoint. Cloudflare Workers (serverless functions that run on Cloudflare's network) can read and write buckets directly. A public bucket exposes its contents to the internet, so a website can serve user uploads from it. R2 charges no egress fees, the fees that many storage providers charge for data downloaded out of their cloud. It can also copy objects from an older storage provider as they are requested, which allows a gradual migration, and its Data Catalog lets SQL engines query tables stored in R2.
R2 is pay per use: a monthly price per gigabyte stored and per million operations, with a free allowance each month.