Building on Slack just got a lot easier – New tools for developers and admins available today

Self-service sandboxes, custom functions for Bolt and improved integration with your software stack make building for Slack better than ever

By the team at Slack20th June 2024

This week at the TrailblazerDX developer conference, we released a set of features to help you build amazing apps that will bring the power of automation to Slack and help everyone across your organisation to do their best work. These include a new developer portal with enterprise-grade tools, including developer sandboxes, that anyone can use to build and test their apps; a developer beta of custom functions that let you write Slack functions in Python and JavaScript and host them on your own managed infrastructure; and improvements to our developer tools that make it easier to automate building, deploying and maintaining your apps.

Enterprise sandboxes and new developer programme

The first new feature is a new home for Slack developers that gives you space to test your ideas. Starting today, all developers are welcome to a new, free developer portal that will give you access to a suite of enterprise-class tools for building Slack apps – head over to and sign up with the email address that you use for work.

This developer home is also where we provide new tools to help you create, test, deploy and manage your Slack apps. The first of these tools is sandboxes: create your own full Enterprise Grid instances for testing your apps without having to worry about interfering with your production workspace. You can provision up to ten sandboxes that you have full admin control over and where you can deploy as many apps as you like. Because these are full Enterprise Grid workspaces 💰💰💰, you’ll be able to test out your apps on every product tier, with full access to all of Slack’s paid features. This isn’t a tour of the chocolate factory, this is a set of keys and permission – dare we say insistence – to create something that no one’s ever seen before.

Sandboxes are great not just for developers but for admins looking to test out new features or to see how an app that’s in development will work. No need to create a free workspace or request yet another one-off from your IT department. Sandboxes give you complete freedom to create, deploy and test your apps in a safe and fully featured environment.

We built this portal to be a place where you can learn and grow as a developer. A new newsletter showcases apps and best practices and highlights new features to take advantage of. Events highlights where you can meet the Slack team and other developers around the world, in virtual meet-ups or IRL. You’ll be able to keep those connections going with access to the global Slack community. And when it comes time to test new beta features, the developer programme is where you will hear about them first.

Build custom functions for Workflow Builder in Bolt

Starting today, you can create new Bolt for Python and Bolt for JavaScript apps that allow for the creation of custom functions that can be deployed anywhere that a Bolt app can. This means you can write functions in JavaScript or Python that are hosted in your own data centre and available in Workflow Builder. These are available for new Bolt for Python and Bolt for JS applications today as a beta, and we are aiming for a full release this spring with the ability to add functions to your existing Bolt apps, including Bolt for Java.

We launched functions last year as part of the biggest set of new features since the platform emerged from the primordial soup of Slack integrations. This first version of functions made apps more composable, easier to deploy and integrated directly into Workflow Builder. We heard from many of you that you wanted support for languages beyond TypeScript, wanted to deploy them to your own managed infrastructure to access your on-prem data, and wanted to integrate functions into your existing Slack apps.

Starting today, you can start testing functions in Python and JavaScript, and host them wherever you want on net-new apps. And soon you’ll be able to add functions to your existing Bolt apps as well.

Making it easier to build, test and maintain your enterprise apps

Finally, we know you want to build Slack apps in a way that integrates into your own software development life cycle. We’ve added support for scripting with the CLI, including integrating the slack CLI to your CI/CD pipeline. This should make it easier to automate testing and deploying your apps according to the practices that work best for your team. To help you get started, we’ve also written a guide for building the CLI into your DevOps pipeline.

We know that it’s never been easier to write code or even build entire apps, thanks to technology such as coding assistants that can guide you through the development process. As amazing as this technology is, most knowledge workers continue to express some reticence to give over control to an app. Slack remains a preferred way to connect all of your disparate tools together, so you can get more things done, faster, and still be in control of your information.

With a new home for Slack developers, a custom functions beta and better integration into your software development life cycle, our goal is to make building composable, modular apps for Slack as easy as it’s ever been. Get access to sandboxes and everything that the developer community has to offer. Start testing custom function development in Python and JavaScript so your apps can be ready when these features go live, and learn more about integrating Slack’s developer tools into your team’s development pipeline.


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