> ## Documentation Index > Fetch the complete documentation index at: https://docs.canton.network/llms.txt > Use this file to discover all available pages before exploring further. # Daml Studio > VS Code extension for writing Daml smart contracts with syntax highlighting, type checking, and inline diagnostics. Daml Studio is the Visual Studio Code extension for Daml development. It provides real-time feedback as you write Daml code, including type errors, syntax highlighting, and integrated test visualization. ## Installation ### Via dpm The extension is installed automatically when you set up the Daml SDK. Launch it from any Daml project directory: ```bash theme={"theme":{"light":"github-light","dark":"github-dark"}} dpm studio ``` This opens VS Code with the Daml extension activated and your project loaded. You need VS Code 1.87 or above. ### From the VS Code Marketplace You can also install the extension manually from the VS Code Marketplace: 1. Open VS Code 2. Go to the Extensions panel (Ctrl+Shift+X / Cmd+Shift+X) 3. Search for "Daml" 4. Install the Digital Asset Daml extension After installing manually, make sure the Daml SDK is on your `PATH` so the extension can find the compiler. ## Features ### Syntax Highlighting Daml files (`.daml`) get full syntax highlighting for keywords, types, template definitions, choices, and expressions. The color scheme follows VS Code's active theme. ### Type Checking and Inline Errors The extension runs the Daml compiler in the background as you type. Type errors, missing imports, and authorization issues appear as red squiggles in the editor. Hover over an error to see the full diagnostic message. For example, if you reference a party that is not in scope: ```haskell theme={"theme":{"light":"github-light","dark":"github-dark"}} template MyContract with owner : Party where signatory missingParty -- Error: Variable not in scope ``` The extension underlines `missingParty` immediately, before you even save the file. ### Go-to-Definition Ctrl+Click (Cmd+Click on macOS) on any identifier to jump to its definition. This works across files within the same package and for standard library functions. ### Code Navigation * **Find all references** -- Right-click an identifier and select "Find All References" to see every usage * **Outline view** -- The sidebar shows the structure of the current file (templates, choices, functions) * **Breadcrumbs** -- The editor header shows the current module and definition path ### Script Results When you open a file containing Daml Script functions, a "Script results" code lens appears above each script. Click it to run the script and see the results in a side panel. The results panel has two views: * **Table view** -- Shows active contracts at the end of the script, with columns indicating which parties can see each contract * **Transaction view** -- Shows every transaction in order, including sub-transactions, useful for understanding authorization flows ### Hover Information Hover over any expression to see its inferred type. This is helpful when working with complex expressions or unfamiliar library functions. ## Troubleshooting ### Extension Not Loading If the extension does not activate when you open a `.daml` file: * Verify the Daml SDK is installed: run `dpm --version` in a terminal * Check that the `daml` binary is on your `PATH` * Reload VS Code (Ctrl+Shift+P, then "Reload Window") * Check the Output panel (View > Output, select "Daml" from the dropdown) for error messages ### SDK Version Mismatch The extension uses the SDK version specified in your project's `daml.yaml`. If you see unexpected errors after upgrading or switching projects: * Run `dpm install` to ensure the correct SDK version is downloaded * Close and reopen VS Code to pick up the new SDK * If errors persist, check the `sdk-version` field in `daml.yaml` matches what you have installed ### Slow Performance on Large Projects For projects with many packages or large dependency trees, the background type checker may take a few seconds to catch up after edits. If you experience delays: * Build the project first with `dpm build` so the compiler can reuse cached artifacts * Close files you are not actively editing to reduce the number of files the extension monitors ## Related Pages * [dpm CLI reference](/sdks-tools/cli-tools/dpm) -- `dpm studio` command and other CLI tools * [Daml SDK](/sdks-tools/sdks/daml-sdk) -- SDK installation and components * [Development environment setup](/appdev/modules/m3-dev-environment) -- Full setup guide for Daml development # Daml Studio Daml Studio is an integrated development environment (IDE) for Daml. It is an extension on top of [Visual Studio Code](https://code.visualstudio.com) (VS Code), a cross-platform, open-source editor providing a [rich code editing experience](https://code.visualstudio.com/docs/editor/editingevolved). ## Install Install Daml Studio by installing the DPM, and ensuring you have [Visual Studio Code](https://code.visualstudio.com) version 1.87 or above installed. ## Configure With Daml Studio open, navigate to `Extensions` on the left (Ctrl+Shift+X). Search for `Daml` and click the Cog icon on the first result, then press settings. The options available are listed in the Reference. ## Operate Navigate to the root of your package (directory containing `daml.yaml`) or project (directory containing `multi-package.yaml`) and run `dpm studio`. This will open Visual Studio Code with the Daml extension installed and running. ### Go to definition Press `F12`, or right click a Daml definition and select "go to definition" to see where a value/type is defined. This will work for dependencies and data-dependencies. [Visual Studio Code Documentation](https://code.visualstudio.com/docs/editor/editingevolved#_go-to-definition). ### Peak definition Use `⌥F12` on Macos, or `Ctrl + Shift + F10` on Windows/MacOS, to peak inline at the definition of a value value/type. [Visual Studio Code Documentation](https://code.visualstudio.com/docs/editor/editingevolved#_peek). ### Hover tooltips Hovering over a Daml value will display its source location and type. Hovering over a Daml type will display its source location. [Visual Studio Code Documentation](https://code.visualstudio.com/docs/editor/editingevolved#_hover). ### Diagnostics Errors or warnings that would be raised by calling `dpm build` will be shown in-line in the IDE. These diagnostics are affected by the flags provided in `build-options`, See Daml Yaml Build Options. ### Daml Snippets Daml IDE provides a set of autocomplete snippets for common daml patterns, such as default template and choice definitions. Typing the start of these definitions (such as the word "template" or "choice") will show these snippets. You can develop your own snippets by following the instructions in [Creating your own Snippets](https://code.visualstudio.com/docs/editor/userdefinedsnippets) to create an appropriate `daml.json` snippet file. ### Daml script results Above any top level definition that would be run as part of `dpm test` (See dpm test), a "Script Results" button will appear. Clicking this will open a side panel, with the result of running that test, along with information about logging and the ledger state. Changing the Daml code for that test will update the side panel in real time, and will show an error if the code does not compile. At the top of the panel is a toggle button between `table` and `transaction` view. **Table view** Table view shows all contracts that were created during the test, as well as their payloads and which parties observed them. There are also check boxes on the top for showing contracts that were archived, and for more information about which parties they were divulged to. When using the `Show detailed disclosure` checkbox, the party observed contract column will show one of the following: * `S`, the party sees the contract because they are a signatory on the contract. * `O`, the party sees the contract because they are an observer on the contract. * `W`, the party sees the contract because they witnessed the creation of this contract, e.g., because they are an actor on the `exercise` that created it. * `D`, the party sees the contract because they have been divulged the contract, e.g., because they witnessed an exercise that resulted in a `fetch` of this contract. **Transaction view** Transaction view shows the generated transaction, logs and test result. Various IDs within this view, such as template names, contract IDs, transaction IDs, etc. will be links to their respective source. ### Multi-package environments Daml Studio will create a separate compiler environment for each package, based on the contents of each `daml.yaml`. If a `multi-package.yaml` is present (in the directory that Daml Studio was opened in), Daml Studio will allow Jump To Definition to jump to packages listed in this file, rather than unpacked from the package-database. Package environments will be reloaded whenever the relevant `daml.yaml` file is changed, or any dependencies DARs are updated. As a result, running `dpm build --all` will usually cause every package environment to reload. For changes across dependencies (i.e. change to a datatype defined in one packaged and used in another), the former packages .dar file must be rebuilt for the latter to use these changes. Package environments do not need to use the same SDK version as your main package, Daml Studio will use the version specified in the relevant packages `daml.yaml` to give diagnostics for that file. See Automatic SDK Installation for how Daml Studio helps with packages using non-installed Daml SDK Versions. If Daml Studio is unable to start a package environment for a package, for example an unparsable `daml.yaml`, or missing dependency `.dar`, Daml Studio will show this diagnostic at the top of the package's `daml.yaml` file. Saving this file will trigger Daml Studio to try again. **Root Multi-package SDK** As discussed above, each package runs its own environment, these environments are managed by the root environment, which if not specified, will be the most recent SDK on your system. You can override this version by providing a `daml.yaml` file at the root of your project (i.e. next to the `multi-package.yaml`) containing only the following: ```yaml theme={"theme":{"light":"github-light","dark":"github-dark"}} sdk-version: ``` ### Jump to definition for dependencies Daml Studio supports unpacking dependencies to allow the user to jump to their source code. However, Daml Studio can only do this is the packages DAR is available. A .dar file will hold the source code it the main package it contains, but not to any dependencies that have been bundled with it. If you wish to jump to the source code on these transitive dependencies, their .dar paths can be listed either in the `daml.yaml` of your main package, or under the `dars:` field in the `multi-package.yaml`, which exists only for this purpose. An example is given below: ```yaml theme={"theme":{"light":"github-light","dark":"github-dark"}} packages: - my-package - libs/my-lib dars: - ./dars/my-transitive-dependency-1.0.0.dar ``` ### Automatic SDK installation If you open a `.daml` file for a package using an SDK version you do not have installed, Daml Studio will show a notification for installing this SDK version. This notification will then show status for the installation, and includes a cancel button. Daml Studio cannot provide diagnostics to a package for which the SDK version is not installed. ### Directory Envrionment Tools (direnv) Tools like `direnv` are commonly used to set up dependencies and import environment variables for use with environment variable interpolation support. To make this work in Daml Studio, you need a VSCode extension that sets this up for other extensions. In the case of `direnv` specifically (i.e. you have a `.envrc` file), we recommend using [this direnv extension by Martin Kühl](https://marketplace.visualstudio.com/items?itemName=mkhl.direnv), which we have verified is compatible. Other direnv extensions may not correctly pass environment information to the Daml Studio extension. If the Daml extension detects a `.envrc` file, it recommends this extension within the IDE with the following message: ``` Found an .envrc file but the recommended direnv VSCode extension is not installed. Daml IDE may fail to start due to missing environment variables. Would you like to install the recommended direnv extension or attempt to continue without it? ``` It also provides a link to the extension on the VS Code extension marketplace. ## Limitations * Jumping to non-local dependencies does not currently retain the build-options and module-prefixes for that package. This means that if you jump to a dependency that requires either of these to build, the editor shows errors in the source code. * Some links in the Script Results tab may not resolve correctly cross-package. * Packages with symlinks between the daml.yaml and source files may not give correct intelligence. ## Upgrade Daml Studio will upgrade as Daml Assistant upgrades, and as new versions of the extension are published to VSCode marketplace. See Daml Assistant Upgrade and the `--replace` flag in Reference for more details. ## Decommission Open Visual Studio Code (not `dpm studio`), navigate to `Extensions` on the left (Ctrl+Shift+X). Search for `Daml` and click the top result. This will open the `Extension: Daml` page, which includes an uninstall button to the right of the Daml Extension icon. Follow the Daml Assistant Decomission for removal Daml itself. ## Troubleshoot * `Error loading webview: Error: Could not register service worker ...` when clicking `Script Results` This can occur when you have multiple VSCode instances in the same project. Fix this by closing VSCode, and killing all processes: * Linux/MacOS: `killall code` * Windows: Open Task Manager (Ctrl + Shift + Esc) and kill all VSCode processes. * Issues with processes left behind, or read/write lock errors on build with Daml Studio open > Please report this on the [GitHub Issues page](https://github.com/digital-asset/daml/issues), then disable `Multi-IDE` support as shown in the Reference. * Any other issues It may help to read the Daml Studio output logs, and include them in a bug report on [GitHub Issues page](https://github.com/digital-asset/daml/issues). On the top bar, click View->Output, the on the drop-down menu on the top right of the new window (May currently say `Tasks`), select `Daml Language Server`. ## Contribute See the open source GitHub repository: `https://github.com/digital-asset/daml` ## References ### Daml Studio Extension options The Daml Studio Extension contains the following options: * `Autorun All Tests` Default: false Run all tests in a file once it's opened, instead of waiting for the user to select individual tests. * `Extra Arguments` Extra arguments passed to `damlc ide`. This can be used to enable additional warnings via `--ghc-option -W` Consider using the `build-options` field in the `daml.yaml` before resorting to this option, as these options are more difficult to distribute. * `Log Level` Default: Warning Sets the logging threshold of the daml-ide and multi-ide * `Multi Package Ide Support` Default: true Enables support for multi-package projects in the IDE * `Profile` Default: false Profile the daml ide plugin, may effect performance * `Telemetry` Default: From consent popup Controls whether you send Daml usage data to Canton Network ### Daml Studio CLI options The `dpm studio` CLI command (which opens the Daml Studio editor) takes the following flags: * `--replace` Value: `published`, `always`, `never` Default: `published` This flag controls when the `dpm studio` command replaces the VSCode extension in your editor. * `published` will always use the most recent published (to the VSCode marketplace) version of the Daml Studio VSCode extension. * `always` will use the extension bundled with whichever SDK version is being used (as selected by the `daml.yaml`, See Daml Assistant version management. * `never` will not change the extension that is installed. If you need to use a much older version of Daml, you may need to use `--replace=always` to launch Daml Studio correctly.