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What you see today is just the start. In fact, the real value will become apparent as we build products that utilize the BSR as a foundation to understand and reason about API schemas, including in real time.

Here, we outline some (but not all!) of the products on our roadmap. We'd love your input and feedback, Contact us to discuss any of the below, or any other products you'd like to see.

The Buf Schema Registry (BSR)#

Remote client and server library generation#

One of the promises of the BSR is to allow the generation of your APIs on demand. At a high level, we want to enable modules to have stubs generated on-demand, for every version, for every possible Protobuf plugin, with consumption via language-native mechanisms.

This feature is currently available for Buf's Go Module Proxy which is currently in alpha. Given a module, such as, you can consume generated code for:

  • Plugin protoc-gen-go version 1.4.0
  • Plugin protoc-gen-go-grpc version 1.0.0

All via a go command that results in a Go module:

$ go get

Similar mechanisms exist for other languages, such as:

  • NPM packages
  • Maven repositories
  • Python packages
  • Ruby gems
  • Tarballs

This will enable users to consume Protobuf definitions without ever interacting with buf, instead consuming APIs as if they were third-party libraries in their native coding language. This can be especially powerful as we move towards a world where Protobuf is used beyond internal APIs, but for external APIs as well.

Enforced linting and compatibility#

The BSR currently leans on the module author to verify that their proposed commit is backwards-compatible with previous commits before the module is pushed. buf breaking does help, of course, but mistakes happen and users might forget to instrument this in their CI pipeline.

Instead, we can let users configure backwards-compatibility for the module itself so that it's enforced on the server side. Better yet, the same could be done for buf lint, too. This unlocks huge potential with respect to updating dependencies. By virtue of Protobuf API compatibility, if the latest commit is guaranteed to be compatible with all of its previous commits, consumers can always resolve the latest commit for each of their dependencies and authors never need to worry about breaking their customers.

Solving the diamond dependency problem#

It's only a matter of time until the Diamond Dependency Problem manifests itself in dependency management systems. Historically, these issues can only be verified at build time because the dependency management solution attempts a "best effort" whereby the developer tries to compile their code after their dependencies have been resolved but fails to do so due to backwards-incompatible API changes.

By virtue of Protobuf API compatibility, rules and Buf's powerful compatibility tooling, the BSR is uniquely positioned to solve this problem. The BSR receives all of the dependencies requested for a specific module, and can systematically determine the latest version that is compatible with all of the provided versions with Buf's compatibility checker. If such a version does not exist, the BSR can give an informative error that describes exactly why the dependencies could not be resolved, and the developer can simply adjust their requirements as needed to proceed.

Reflection Service#

The BSR holds all of your Protobuf API definitions so it can easily act as a reflection server for your Protobuf messages. This typically involves exposing a set of reflection endpoints on your server, but this is no longer required because the BSR has all of your definitions and it can host this functionality for you.

Fully qualified Protobuf import paths#

Today, Protobuf import paths are relative to user specified include directories. This may be the single most painful lesson for new users to learn, so we want to get rid of it entirely. Imagine importing rather than google/api/http.proto. The BSR will support this transition in a backwards-compatible manner, so that you can transition to using fully qualified import paths if you like in your project.


A large part of the BSR API is usable with the buf CLI, but we will soon expose the BSR API so that you can build your own tools and integrations with it.


Better IDE integration#

Buf currently supports both a vim plugin and a VSCode plugin to provide Protobuf linting in these editors. But we recognize that we can do a lot more in this area, such as formatting your Protobuf files on save (via the formatter mentioned above), and a full-fledged Protobuf language server, which involves implementing the Language Server Protocol (LSP).

With this, you will be able to use more editor features, such as auto-completion and jump-to-definition, to further improve your Protobuf productivity.

Protobuf standard library#

You may already be familiar with Protobuf's Well-Known Types, but these largely act as thin wrappers around primitive values to support zeroable values, such as the BoolValue.

These types are a good start, but we can do so much more with a true standard library of common API definitions. Developers around the world are reinventing the wheel every time they need to define their PostalAddress, Currency, and URI messages. Buf will address this by defining a generic set of such types that can be dropped-in to your application so that you can focus on writing your business logic.

API versioning#

We recognize that backwards-incompatible changes are inevitable. API authors should do everything they can to prevent breaking changes from happening, but everyone makes mistakes and/or justifies that the tradeoff is worth it (for whatever reason).

With that said, the team is exploring an API transcoding solution inspired by Stripe's API versioning strategy. In short, Stripe has built infrastructure that lets them freely make breaking changes without ever breaking their clients. An API transformation layer sits between their client and their server that translates old API structures into their current API structures.

The BSR is perfectly positioned to bring this solution to Protobuf users. The BSR tracks the entire history of your module, and can theoretically apply a series of changes (specified in a changelog) to your API so that you can stop worrying about API compatibility entirely.