Ionic App Development

Ionic App Development

General Ionic Framework development — core concepts, component reference, CLI usage, layout, theming, utilities, development workflow, and troubleshooting.

Prerequisites

1. Node.js (latest LTS) installed.
2. Ionic CLI installed globally (npm install -g @ionic/cli).
3. An existing Ionic project. For creating a new Ionic app, use the ionic-app-creation skill.

Agent Behavior

• Auto-detect the framework. Check package.json for @ionic/angular, @ionic/react, or @ionic/vue to determine the framework in use. Adapt code examples accordingly.
• Route to reference files. This skill is an overview that routes agents to specific reference files for detailed component APIs and topic-specific guidance.
• Do not duplicate framework-specific skills. For Angular, React, or Vue specific patterns, refer to the respective framework skill.

Core Concepts

How Ionic Works

Ionic Framework is a UI toolkit for building cross-platform apps using web technologies (HTML, CSS, JavaScript/TypeScript). It provides a library of pre-built UI components that adapt their styling to the platform (ios or md mode).

• Components are custom HTML elements (Web Components) prefixed with ion- (e.g., <ion-button>, <ion-content>).
• Platform modes: Ionic renders components differently based on the platform. iOS devices use the ios mode; Android and all other platforms use the md (Material Design) mode. The <html> element receives a class (ios or md) that enables platform-specific styles.
• Capacitor integration: Ionic apps use Capacitor to access native device features. Ionic handles the UI; Capacitor handles native APIs. See the capacitor-app-development skill for Capacitor-specific guidance.

Page Lifecycle

Ionic provides lifecycle events on top of the framework's own lifecycle hooks. These fire when a page is navigated to or from:

These are in addition to the framework-specific lifecycle hooks (e.g., Angular's ngOnInit, React's useEffect, Vue's onMounted). Use Ionic lifecycle events for tasks that should run each time a page becomes visible (e.g., refreshing data), since some navigation strategies cache pages.

Component Reference

Ionic provides 80+ UI components. Detailed API documentation for each component is organized into reference files by category. Each reference file covers properties, events, methods, slots, CSS shadow parts, and CSS custom properties.

When the user needs help with a specific component, read the corresponding reference file.

Ionic CLI

The Ionic CLI is the primary tool for developing Ionic apps. Below are the most commonly used commands. Run ionic --help for the full and always up-to-date command list.

Installation

npm install -g @ionic/cli

If upgrading from the legacy ionic package:

npm uninstall -g ionic
npm install -g @ionic/cli

Key Commands

ionic serve Options

For framework-specific CLI options, pass them after --:

ionic serve -- --proxy-config proxy.conf.json

Layout

Read references/components-layout.md for the full API reference for layout components.

Grid System

Ionic uses a 12-column flexbox grid system (ion-grid, ion-row, ion-col). Columns expand to fill the row evenly unless a size attribute is specified (1-12).

Responsive breakpoints:

CSS Utility Classes

Ionic provides responsive CSS utility classes for common styling needs:

• Text: .ion-text-center, .ion-text-start, .ion-text-end, .ion-text-wrap, .ion-text-nowrap, .ion-text-uppercase, .ion-text-lowercase, .ion-text-capitalize
• Padding: .ion-padding, .ion-padding-top, .ion-padding-bottom, .ion-padding-start, .ion-padding-end, .ion-padding-vertical, .ion-padding-horizontal, .ion-no-padding
• Margin: .ion-margin, .ion-margin-top, .ion-margin-bottom, .ion-margin-start, .ion-margin-end, .ion-margin-vertical, .ion-margin-horizontal, .ion-no-margin
• Display: .ion-display-none, .ion-display-block, .ion-display-flex, .ion-display-inline, .ion-display-grid
• Float: .ion-float-left, .ion-float-right, .ion-float-start, .ion-float-end
• Flex: .ion-justify-content-center, .ion-align-items-center, .ion-flex-row, .ion-flex-column, .ion-flex-wrap, .ion-flex-nowrap
• Border: .ion-no-border

All utility classes support responsive breakpoint suffixes: ion-text-{breakpoint}-center (e.g., .ion-text-md-center applies at 768px+).

Theming

Colors

Ionic provides nine default colors: primary, secondary, tertiary, success, warning, danger, light, medium, dark. Apply via the color attribute on components:

<ion-button color="primary">Primary</ion-button>
<ion-button color="danger">Danger</ion-button>

Each color has six CSS custom properties:

• --ion-color-{name} — Base color value
• --ion-color-{name}-rgb — Base color in RGB format
• --ion-color-{name}-contrast — Text color for readability
• --ion-color-{name}-contrast-rgb — Contrast color in RGB format
• --ion-color-{name}-shade — Darker variant (active/pressed states)
• --ion-color-{name}-tint — Lighter variant (hover states)

To customize a color, override all six variables in :root:

:root {
  --ion-color-primary: #3880ff;
  --ion-color-primary-rgb: 56, 128, 255;
  --ion-color-primary-contrast: #ffffff;
  --ion-color-primary-contrast-rgb: 255, 255, 255;
  --ion-color-primary-shade: #3171e0;
  --ion-color-primary-tint: #4c8dff;
}

To add a custom color, define the CSS variables and create a class:

:root {
  --ion-color-favorite: #69bb7b;
  --ion-color-favorite-rgb: 105, 187, 123;
  --ion-color-favorite-contrast: #ffffff;
  --ion-color-favorite-contrast-rgb: 255, 255, 255;
  --ion-color-favorite-shade: #5ca56c;
  --ion-color-favorite-tint: #78c288;
}

.ion-color-favorite {
  --ion-color-base: var(--ion-color-favorite);
  --ion-color-base-rgb: var(--ion-color-favorite-rgb);
  --ion-color-contrast: var(--ion-color-favorite-contrast);
  --ion-color-contrast-rgb: var(--ion-color-favorite-contrast-rgb);
  --ion-color-shade: var(--ion-color-favorite-shade);
  --ion-color-tint: var(--ion-color-favorite-tint);
}

Global CSS Variables