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Codcel Desktop Application

The Codcel Desktop application is the primary tool for transforming Excel spreadsheets into production-ready software. It runs entirely on your local machine and is available for Windows, macOS, and Linux.

Download the latest version from codcel.io.

First Launch and Onboarding

When you open Codcel for the first time, an onboarding wizard guides you through the initial setup:

  1. Welcome -- an introduction to Codcel
  2. Quick Start -- a brief overview of the workflow
  3. Projects Location -- select a default directory where your Codcel projects will be stored

The projects location is saved to your user configuration (~/codcel.toml) and is used as the default directory when creating or opening projects. You can change it later from the Home page.

After completing the onboarding, you will not see it again on subsequent launches.

Home Page

The Home page is the first screen you see after onboarding. It presents two options:

Create a New Project

  1. Click the Create button
  2. Enter a project name in the dialog that appears
  3. Select a directory for the project (defaults to your configured projects location)
  4. Click Create Project

Codcel creates a new folder with the project name inside the selected directory and initialises a codcel.toml configuration file.

Open an Existing Project

  1. Click the Open button
  2. Browse to the folder of an existing Codcel project
  3. Click Open Project

Codcel looks for a codcel.toml file in the selected directory to confirm it is a valid project. If the file is not found, an error message is shown.

The version number is displayed in the bottom-left corner of the Home page.

Project Dashboard

After creating or opening a project, you enter the Project Dashboard. This is where you do all your work: importing files, configuring settings, and generating code.

The dashboard uses a drawer-based sidebar for navigation. Click the menu button (three horizontal lines) in the top-right corner to open the sidebar.

The sidebar contains the following items:

Always visible: - Business Specs -- import and manage your Excel files - Settings -- configure formatting and calculation options

Visible after importing Excel files: - Generate Project -- select output targets and generate code

Visible after generating code (one entry per enabled output type): - Rust Calculation Library, Rust Model Library, Tables - WASM Calculation Library, Fullstack UI, RESTful Server - Web Clients (Rust, Java, Kotlin, C#, Python, Go, JavaScript, TypeScript, Swift) - Calculation Libraries (Java, Kotlin, C#, Visual Basic, Python, Go, Swift) - RESTful Servers (Java, Kotlin, C#, Go) - OpenAPI Document, Command Line, MCP Server, JNI, FFI Library

Each output-type entry in the sidebar links to a view where you can inspect the generated source code for that target.

Tutorial Overlay

The first few times you open a project, a brief tutorial overlay highlights the key areas of the dashboard. You can dismiss the tutorial or choose not to see it again.

Importing Excel Files

The Business Specs view is where you import your Excel spreadsheets.

How to Import

You can import files in two ways:

  • Drag and drop files directly into the import area
  • Click Browse to open a file picker

Supported Formats

Format Extension Recommendation
Excel Workbook .xlsx Recommended -- best compatibility
Excel 97-2003 Workbook .xls Supported -- older format with fewer features
Excel Macro-Enabled Workbook .xlsm Supported -- macros/VBA are ignored
Excel Binary Workbook .xlsb Supported -- may have parsing limitations for complex workbooks
Excel Add-In .xla Supported
Excel Macro-Enabled Add-In .xlam Supported -- macros/VBA are ignored
OpenDocument Spreadsheet .ods Supported

Notes: - .xlsx is recommended for best compatibility and most reliable parsing - Macros and VBA are not transpiled -- Codcel reads formula logic only, not macro code - .xlsb (binary format) is supported but .xlsx is preferred for complex workbooks - .xls (legacy format) supports fewer modern Excel features

What Happens on Import

When you import a file:

  1. The file is copied into the business_specs/ subdirectory of your project
  2. A progress indicator shows the copy status
  3. The file is registered in the [files] section of codcel.toml
  4. The Generate Project option becomes available in the sidebar

You can import multiple files. After importing, you can view the list of imported files and open the business_specs/ folder in your system's file explorer.

For guidance on preparing your Excel files before import, see the Excel Guidelines.

Configuring Settings

Open the Settings view from the sidebar to configure how Codcel interprets your Excel data and generates code.

Settings are saved per project in the codcel.toml file. Click Save to persist your changes.

For a full reference of all available settings, see the Settings Reference.

Key Settings

  • Decimal Separator and Thousands Separator -- control number formatting to match your locale
  • Currency Symbol -- set the currency symbol used in generated code
  • Use Excel Rounding -- enable Excel-compatible rounding behaviour (15 significant digits)
  • Strict Type Conversion -- control how Codcel handles implicit type conversions
  • Enable Iterative Calculation -- allow circular references to be resolved iteratively, with configurable maximum iterations and convergence threshold

Generating Code

Once you have imported at least one Excel file, the Generate Project view becomes available in the sidebar.

Selecting Output Targets

The Generate Project view displays a list of checkboxes for each output target. The Rust Calculation Library is always selected and cannot be disabled -- it forms the core of all generated projects.

Additional output targets are grouped into categories such as:

  • Servers -- REST APIs in Rust, Java, Kotlin, C#, Go
  • Web Clients -- client libraries in multiple languages
  • Calculation Libraries -- standalone calculation code in Java, Python, C#, and more
  • Full-Stack -- complete web applications with UI
  • Integration -- OpenAPI specs, CLI tools, MCP servers, JNI/FFI bindings

Some output targets require you to be logged in with a Codcel account.

Running the Generation

  1. Select the output targets you want
  2. Click Generate
  3. A progress bar shows the generation status
  4. When complete, the generated code appears in your project directory

After generation completes, new entries appear in the sidebar for each enabled output type, where you can view and inspect the generated source code.

Authentication

Codcel can be used without an account for generating the core Rust Calculation Library. To access additional output targets, you need to log in.

Logging In

  1. Click the Login button in the header bar
  2. Enter your email address
  3. Click Send Magic Link
  4. Check your email and click the verification link
  5. Return to the Codcel app and click Complete

Your session is maintained securely. Access tokens are stored in memory and refresh tokens are stored in your operating system's secure keychain. Your session refreshes automatically in the background.

Logging Out

Click the user menu in the header and select Logout. When you log out, any premium output targets you had selected will be deselected.

Theme and Language

Themes

Codcel supports multiple visual themes including both light and dark options. Click the theme selector in the header to browse and switch themes.

Language

The user interface is available in 10 languages:

Language Code
English en
Spanish es
Portuguese pt
French fr
German de
Bulgarian bg
Italian it
Japanese ja
Korean ko
Chinese zh

You can change the UI language from the application settings. The language preference is stored in your global configuration file (~/codcel.toml).

Project File Structure

After creating a project and generating code, your project directory will contain:

my-project/
├── codcel.toml              # Project configuration
├── business_specs/          # Imported Excel files
│   └── spreadsheet.xlsx
├── src/                     # Generated Rust source code
└── generated/               # Generated projects for other languages
    ├── rust-calculation/
    ├── java-calculation/
    ├── web-client/
    └── ...

The codcel.toml file contains all project settings, file references, and generation options. For details on its structure, see the Settings Reference.

Next Steps