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Bruno can open an existing OpenAPI Specification (OAS) and create a new one. A new spec can start blank, be generated from a Bruno collection, or be fetched from a URL hosting an OpenAPI spec.

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Viewing Existing OAS Files

You can view and interact with existing OAS files in Bruno using a SwaggerUI-like interface:
  1. Enable OpenAPI Spec feature from Preferences to start working with it.
enable-openapi-spec
  1. Select Open API Spec from dropdown in left hand side menu.
open-open-api
  1. Browse and select your OAS file (.yaml or .json)
  2. The specification will open in a dedicated section of your Bruno sidebar
view-open-api

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Creating New OAS Files

  1. In the sidebar, click + next to API Specs.
  2. Select Create API Spec.
Source has three options: Blank Spec, Bruno Collection, and Spec URL. Every source includes Name and Location. Location is filled in for you: a named workspace uses its apispec folder, and the default workspace uses the default location from Preferences (or that workspace’s apispec folder when no default location is set). Optionally, use Browse to select the location, then click Create.

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Blank Spec

Leave Source on Blank Spec and enter a Name. Bruno writes an empty .yaml file.

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Bruno Collection

Select Bruno Collection to generate an OpenAPI 3 spec from the requests in a collection. From workspace lists the collections in the active workspace. Pick one from the dropdown. Name is filled from the collection name. When that collection has environments, an Environment field appears and the selected environment’s variables are written into the spec. Create API Spec from a collection in the workspace From filesystem browses for a collection folder on disk. Select From filesystem, click the folder field, and choose a folder that contains bruno.json or opencollection.yml. Name is filled from the folder name.

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Spec URL

Select Spec URL and enter an http or https URL that returns an OpenAPI 3.x document (YAML or JSON). Bruno fetches the URL and checks that it is an OpenAPI 3.x specification. Name is filled from the spec’s info.title. The saved file is .json when the response is JSON, and .yaml otherwise. Create API Spec from a hosted OpenAPI URL

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Editing Your OAS File

Once created, you can edit your OAS file in Bruno’s built-in editor:
  1. The editor provides syntax highlighting
  2. Use the sidebar to navigate through different sections of your API
  3. Add or modify endpoints, parameters, and responses
  4. Include examples and descriptions for better documentation
write-api-spec