sileo-svelte

Physics-based toast notifications for Svelte 5.

Unofficial Svelte 5 port of Sileo by Aaryan.

Installation

npm install sileo-svelte

Quick Start

1. Mount the toaster once

<!-- src/routes/+layout.svelte -->
<script>
    import { Toaster } from 'sileo-svelte';
    import 'sileo-svelte/styles.css';

    let { children } = $props();
</script>

{@render children()}

<Toaster position="top-right" />

2. Trigger toasts from anywhere

<script>
    import { sileo } from 'sileo-svelte';
</script>

<button onclick={() => sileo.success('Saved', 'Your changes have been saved.')}>Save</button>

<Toaster /> Props

Only one <Toaster /> is needed in your app.

Prop	Type	Default	Description
position	SileoPosition	'top-right'	Default viewport for new toasts. Per-toast position still overrides this.
offset	number | string | SileoOffsetConfig	undefined	Offset from screen edges. Number values are treated as px.
options	Partial<SileoOptions>	undefined	Global defaults merged into every toast call. Per-toast fields win. classes and styles are merged per-key.
children	Snippet	undefined	Optional content rendered before toast viewports.

SileoOffsetConfig:

type SileoOffsetConfig = Partial<{
    top: number | string;
    right: number | string;
    bottom: number | string;
    left: number | string;
}>;

SileoPosition:

'top-left' | 'top-center' | 'top-right' | 'bottom-left' | 'bottom-center' | 'bottom-right';

sileo API

All creation methods return the toast id: string.

Creation methods

show(input: SileoInput, description?: SileoOptions['description']): string
success(input: SileoInput, description?: SileoOptions['description']): string
error(input: SileoInput, description?: SileoOptions['description']): string
warning(input: SileoInput, description?: SileoOptions['description']): string
info(input: SileoInput, description?: SileoOptions['description']): string
action(input: SileoInput, description?: SileoOptions['description']): string
loading(input: SileoInput, description?: SileoOptions['description']): string

SileoInput:

type SileoInput = SileoOptions | string;

Examples:

sileo.success({ title: 'Saved' });
sileo.success('Saved');
sileo.success('Saved', 'Your changes have been saved.');

// loading defaults to duration: null unless explicitly provided
const id = sileo.loading('Uploading...');
sileo.update(id, { state: 'success', title: 'Uploaded' });

Scoped defaults

Use sileo.with(defaults) to avoid repeating common options.

const billingToasts = sileo.with({
    position: 'bottom-right',
    duration: 4000,
    fill: '#121212'
});

billingToasts.success('Invoice paid');
billingToasts.error('Payment failed', 'Please retry with another card.');

Defaults are merged recursively for classes and styles, and shallow-merged for other fields.

Promise helper

promise<T>(
  promise: Promise<T> | (() => Promise<T>),
  opts: SileoPromiseOptions<T>
): Promise<T>

sileo.promise(() => fetch('/api/upload', { method: 'POST' }), {
    loading: { title: 'Uploading' },
    success: () => ({ title: 'Done', description: 'File uploaded successfully!' }),
    error: (err) => ({
        title: 'Failed',
        description: err instanceof Error ? err.message : 'Upload failed.'
    })
});

SileoPromiseOptions<T>:

Option	Type	Required	Description
id	string	No	Existing toast id to morph instead of creating a new one.
loading	Pick<SileoOptions, 'title' | 'icon'>	Yes	Pending state content.
success	SileoOptions | ((data: T) => SileoOptions)	Yes	Success state content.
error	SileoOptions | ((err: unknown) => SileoOptions)	Yes	Error state content.
action	SileoOptions | ((data: T) => SileoOptions)	No	If provided, replaces success state.
position	SileoPosition	No	Position override for the promise toast.

Update and dismissal

update(id: string, opts: SileoOptions & { state?: SileoState }): void
dismiss(id: string): void
close(id: string): void
clear(position?: SileoPosition): void

• update: morphs content/state in place.
• dismiss: immediate exit animation.
• close: collapse first, then exit.
• clear: remove all toasts (or a specific viewport).

SileoOptions

Field	Type	Default	Description
title	string	State name	Header title.
description	string | Snippet	undefined	Expanded body content.
position	SileoPosition	Toaster position	Per-toast viewport override.
duration	number | null	6000	Auto-dismiss timeout in ms. null keeps it persistent.
icon	Snippet | null	State icon	Custom icon snippet; null hides icon.
classes	SileoClasses	undefined	Per-part class overrides.
styles	SileoStyles	undefined	Per-toast color variable overrides (Tailwind-free).
fill	string	'#1c1c1e'	Toast background color.
roundness	number	18	Corner radius.
autopilot	boolean | { expand?: number; collapse?: number }	true	Automatic expand/collapse behavior.
button	SileoButton	undefined	Action button shown in expanded body.

SileoClasses:

interface SileoClasses {
    title?: string;
    description?: string;
    badge?: string;
    button?: string;
}

SileoStyles:

interface SileoStyles {
    titleColor?: string;
    descriptionColor?: string;
    badgeColor?: string;
    badgeBackground?: string;
    buttonColor?: string;
    buttonBackground?: string;
    buttonHoverBackground?: string;
}

SileoButton:

interface SileoButton {
    title: string;
    onClick: (id: string) => void;
}

SileoState:

'success' | 'loading' | 'error' | 'warning' | 'info' | 'action';

Practical Examples

Custom appearance

sileo.success({ title: 'Dark', description: 'Custom background.', fill: '#1a1a2e' });
sileo.info({ title: 'Square', description: 'Reduced roundness.', roundness: 4 });
sileo.warning({ title: 'Manual', description: 'Hover to read.', autopilot: false });

Styling with classes and styles

// Class-based styling
sileo.action({
    title: 'Class styling',
    description: 'Uses classes.title/classes.description/classes.button',
    classes: {
        title: 'text-foreground',
        description: 'text-foreground',
        button: 'text-primary-foreground hover:bg-primary/90'
    },
    button: { title: 'Close', onClick: (id) => sileo.close(id) }
});

// Variable-based styling (recommended if utility extraction is inconsistent)
sileo.action({
    title: 'Variable styling',
    description: 'Uses styles.*',
    styles: {
        titleColor: 'var(--foreground)',
        descriptionColor: 'var(--foreground)',
        buttonColor: 'var(--primary-foreground)',
        buttonBackground: 'var(--primary)',
        buttonHoverBackground: 'color-mix(in oklch, var(--primary) 85%, black)'
    },
    button: { title: 'Close', onClick: (id) => sileo.close(id) }
});

Tailwind note:

• If utility classes are passed inside JS strings (like options.classes.button), Tailwind may not always detect them.
• For Tailwind v4, safelist them via @source inline("text-foreground text-primary-foreground hover:bg-primary/90").

Reusing a toast id

const id = sileo.loading('Uploading file...');

sileo.update(id, { title: 'Uploading', description: '50%' });
sileo.update(id, { state: 'success', title: 'Done', description: '100%', duration: 4000 });

Svelte snippets for rich content (description and icon)

SileoOptions supports snippets in two places:

• description: rich body content in the expanded area
• icon: custom header icon badge

<script>
    import { sileo } from 'sileo-svelte';
</script>

{#snippet customDescription()}
    <div>
        <strong>Release ready.</strong>
        <p>Click deploy to roll out v2.4.0.</p>
    </div>
{/snippet}

{#snippet rocketIcon()}
    <svg
        xmlns="http://www.w3.org/2000/svg"
        width="16"
        height="16"
        viewBox="0 0 24 24"
        fill="none"
        stroke="currentColor"
        stroke-width="2"
        stroke-linecap="round"
        stroke-linejoin="round"
        aria-hidden="true"
    >
        <path d="M4.5 16.5c-1.5 1.26-2 3.75-2 3.75s2.49-.5 3.75-2l3-3-1.75-1.75z" />
        <path d="M14 10l-4 4" />
        <path d="M16 4l4 4" />
        <path d="M21.17 2.83a2.83 2.83 0 0 1 0 4L11 17l-4-4L17.17 2.83a2.83 2.83 0 0 1 4 0z" />
    </svg>
{/snippet}

<button
    onclick={() =>
        sileo.action({
            title: 'Deploy',
            description: customDescription,
            icon: rocketIcon,
            button: {
                title: 'Run',
                onClick: (id) => sileo.close(id)
            }
        })}>Show Rich Toast</button
>

Notes:

• description and icon both accept either plain values (string / null) or snippets.
• Set icon: null to hide the icon entirely.
• Snippets are also valid in sileo.update(...) payloads, so you can morph to/from rich content.

Advanced workflows (update + promise orchestration)

const id = sileo.loading('Deploying v2.4.0...');

await delay(1000);
sileo.update(id, {
    state: 'info',
    title: 'Uploading build',
    description: 'Artifacts uploaded to edge cache.'
});

await delay(1000);
sileo.update(id, {
    state: 'warning',
    title: 'Running health checks',
    description: 'Smoke tests on 6 regions...'
});

// Final stage: morph same toast through promise lifecycle
sileo.promise(
    async () => {
        await delay(900);
        return await releaseToProduction();
    },
    {
        id,
        loading: { title: 'Rolling out' },
        success: () => ({
            state: 'action',
            title: 'Deployment complete',
            description: 'Traffic switched to v2.4.0.',
            button: {
                title: 'View logs',
                onClick: (toastId) => {
                    openDeploymentLogs();
                    sileo.close(toastId);
                }
            }
        }),
        error: (err) => ({
            title: 'Rollback triggered',
            description: err instanceof Error ? err.message : 'Unknown deploy error',
            duration: null
        })
    }
);

// Action-first flow that morphs into promise states
sileo.action({
    title: 'Update available',
    description: 'Version 2.0 is ready to install.',
    button: {
        title: 'Install now',
        onClick: (id) => {
            sileo.promise(() => installUpdate(), {
                id,
                loading: { title: 'Installing' },
                success: () => ({
                    state: 'action',
                    title: 'Installed successfully',
                    description: 'Restart app to apply the update.',
                    button: {
                        title: 'Restart',
                        onClick: (toastId) => sileo.close(toastId)
                    }
                }),
                error: (err) => ({
                    state: 'action',
                    title: 'Install failed',
                    description: err instanceof Error ? err.message : 'Unknown install error',
                    duration: null,
                    button: {
                        title: 'Retry',
                        onClick: (toastId) => {
                            sileo.promise(() => installUpdate(), {
                                id: toastId,
                                loading: { title: 'Retrying install' },
                                success: { title: 'Retry succeeded', description: 'Update installed.' },
                                error: { title: 'Still failing', description: 'Please check logs.', duration: null }
                            });
                        }
                    }
                })
            });
        }
    }
});

Toaster defaults and viewport offset

<Toaster
    position="bottom-right"
    options={{
        duration: 4000,
        fill: '#0a0a0a',
        roundness: 12
    }}
    offset={{ top: 60, right: 16 }}
/>

Exports

import {
    Toaster,
    sileo,
    type SileoApi,
    type SileoScopedApi,
    type SileoInput,
    type SileoOptions,
    type SileoPosition,
    type SileoState,
    type SileoClasses,
    type SileoStyles,
    type SileoButton,
    type SileoPromiseOptions
} from 'sileo-svelte';

Import CSS separately:

import 'sileo-svelte/styles.css';

CSS Customization

Override these variables globally:

:root {
    --sileo-duration: 600ms;
    --sileo-height: 40px;
    --sileo-width: 350px;

    --sileo-state-success: oklch(0.723 0.219 142.136);
    --sileo-state-loading: oklch(0.75 0 0);
    --sileo-state-error: oklch(0.637 0.237 25.331);
    --sileo-state-warning: oklch(0.795 0.184 86.047);
    --sileo-state-info: oklch(0.685 0.169 237.323);
    --sileo-state-action: oklch(0.623 0.214 259.815);
}

Per-toast variables set via options.styles map to these CSS vars on each toast root:

• --sileo-title-color
• --sileo-description-color
• --sileo-badge-color
• --sileo-badge-bg
• --sileo-button-color
• --sileo-button-bg
• --sileo-button-bg-hover

Credits

• Original library: hiaaryan/sileo
• Original demo: sileo.aaryan.design

License

MIT