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Evidence uses configuration files to customize build behavior, deployment settings, and data sources.

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evidence.config.yaml

The main Evidence configuration file located in your project root.

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Example

deployment:
  basePath: /my-app

components:
  evidenceInclude: true

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Deployment Configuration

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deployment.basePath
string
default:"/"
Base path for the application when deployed to a subdirectory. Used by SvelteKit’s paths.base configuration.

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svelte.config.js

Optional custom SvelteKit configuration file in your project root.

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Supported Customizations

You can extend Evidence’s default SvelteKit configuration: 
/** @type {import('@sveltejs/kit').Config} */
const config = {
  preprocess: [
    // Add custom preprocessors
  ],
  kit: {
    // Customize SvelteKit options (except files)
  }
};

export default config;

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Restrictions

The following configurations are disabled for Evidence projects and will be ignored:
  • extensions - File extensions are fixed to .svelte and .md
  • kit.files - File locations cannot be changed

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Preprocessor Merging

Custom preprocessors are appended to Evidence’s default preprocessors:
  1. Evidence preprocessors (query extraction, etc.)
  2. Component injection
  3. PostCSS preprocessing
  4. Base path transformation
  5. Your custom preprocessors

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Source Configuration

Data source configuration is stored in sources/[source-name]/connection.yaml.

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Example: PostgreSQL Source

name: my_database
type: postgres
options:
  host: localhost
  database: mydb
  user: ${db_user}
  password: ${db_password}
  port: 5432

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Variable Substitution

Use ${variable} syntax to reference environment variables: 
host: ${db_host}
password: ${db_password}
Set variables: 
EVIDENCE_VAR__db_host=localhost
EVIDENCE_VAR__db_password=secret
See Environment Variables for details.

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Environment Variable Override

You can override any source option using environment variables: 
EVIDENCE_SOURCE__my_database__host=production.db.com
EVIDENCE_SOURCE__my_database__password=prod_secret
Pattern: EVIDENCE_SOURCE__[source_name]__[option] See Environment Variables for details.

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package.json Scripts

Recommended npm scripts for Evidence projects: 
{
  "scripts": {
    "dev": "evidence dev",
    "build": "evidence build",
    "preview": "evidence preview",
    "sources": "evidence sources"
  }
}

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Usage

npm run dev      # Start development server
npm run build    # Build for production
npm run preview  # Preview production build
npm run sources  # Generate data from sources

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Build Configuration

The Evidence build system uses these internal configurations:

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Adapter Configuration

Static adapter settings from svelte.config.js: 
adapter: adapter({
  pages: process.env.EVIDENCE_BUILD_DIR ?? './build',
  strict: false
})
Override the output directory: 
EVIDENCE_BUILD_DIR=./dist evidence build

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File Locations (Fixed)

files: {
  routes: 'src/pages',
  lib: 'src/components'
}
These locations in .evidence/template/ cannot be customized.

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Template Directory

Evidence uses .evidence/template/ as an internal build directory: 
.evidence/template/
├── src/
│   ├── pages/        # Your pages/ directory synced here
│   └── components/   # Your components/ directory synced here
├── static/
│   └── data/         # Generated parquet files
├── sources/          # Your sources/ directory synced here
└── queries/          # Your queries/ directory synced here
This directory is managed automatically by Evidence CLI commands. Manual changes will be overwritten.

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