Local Bun Development with FlyEnv

Bun is a JavaScript and TypeScript runtime that also bundles a package manager, bundler and test runner in a single executable. It is used as an alternative to Node.js for servers, scripts and frontend tooling. FlyEnv's Bun module covers the essentials of local Bun work in one place: install Bun versions from static builds, decide which one your terminal bun command resolves to, and bind each project to its own runtime. The module has three tabs — Projects, Service and Version Manager — focused on version installation, PATH control and project runtimes.

Bun version management

Install Bun versions side by side from Bun → Version Manager and keep them all available at once.

• Static builds only: Bun is installed from a Static online list on every platform — macOS, Linux and Windows alike. The Homebrew and MacPorts sources offered for other runtimes are not available for Bun.
• Custom directories: point FlyEnv at any directory containing your own Bun build and it appears in the list next to the managed versions.
• Managed install location: versions are unpacked into FlyEnv's app directory under bun/<version>/, and each installation is detected through its real bun --version output.
• Post-install setup: after installing a version, FlyEnv runs bun completions so shell completion works, and on macOS it clears the quarantine attribute from the downloaded binary.

Command-line version switching

Nothing runs as a service here: FlyEnv has no Bun daemon, so the Service tab is actually an installed-versions table focused on PATH management.

• Terminal version switching: choose which installed version the terminal bun command resolves to. FlyEnv handles your PATH for you — adding the version's bin directory when you select it, removing it when you switch away — and shows whether the active PATH entry was set by FlyEnv or another tool. See the system PATH environment guide for how PATH management works.
• Per-version alias and remark: give each installation its own short alias and note, so similar builds stay distinguishable in the list.
• Housekeeping: every row shows where the version is installed, and versions you no longer need can be removed from the table.

Project-level Bun runtimes

In Bun → Projects, register each project folder and bind it to a specific Bun version instead of relying on whichever version happens to be in PATH.

• Per-project runtime: the version choice is stored in a .flyenv file inside the project directory, so terminals and editors launched from FlyEnv pick up the right Bun automatically. See the project-level runtime environment guide and the Per-Project Runtimes feature for how the mechanism works.
• Run as service: optionally run a project directly from FlyEnv with a custom start command or run file, a TCP port exposed as a http://127.0.0.1:<port> link, environment variables set inline or from a file, and a sudo flag on macOS and Linux.
• Open-in tools: jump from a project row into the system terminal or an editor with the project environment loaded.

Related guides, solutions and demos

Continue with a practical guide, solution, demo, or community perspective.

Guides

• Project-level runtime isolation
• System PATH management

Solutions

• Run Strapi locally

Demos

• Browse Bun runtime demos

Compatibility Notes

FlyEnv manages Bun version installation, PATH switching and project runtimes; the Bun module itself has no module-level configuration files, log viewers or admin panel beyond what the Bun binary provides. Installations come from Static builds on every platform, so treat the Download page and current release notes as the source for supported packages.