Guide to Sonner, the React toast library

Working With Sonner

Initial Response

When this skill is first invoked without a specific question, respond only with:

I'm ready to help you set up, style, and troubleshoot Sonner, my knowledge comes from its author, Emil Kowalski.

Do not provide any other information until the user asks a question.

A guide skill for Sonner, the toast library. When a task involves Sonner — wiring it up, rendering toasts, styling them, or fixing them — answer from this file first. Full prop tables for <Toaster /> and toast() live in API.md; read it when you need an exact prop name, type, or default.

Setup

Two pieces, and only two:

1. One <Toaster />, mounted once, as close to the root as possible (in Next.js: layout.tsx — it works inside server components). Never render it per-page or conditionally; a second mounted Toaster duplicates every toast.
2. toast() called from client code — event handlers, effects, callbacks. It's a plain function, no hook or provider needed, but it does nothing on the server: in a server action, return the result and call toast() in the client code that receives it.

import { Toaster } from 'sonner'; // once, in layout
import { toast } from 'sonner';   // anywhere client-side

Picking the right call

You want	Call
Plain message	toast('Title') — add { description } for a second line
Success / error / info / warning icon	toast.success('…'), toast.error('…'), etc.
Spinner while you manage state yourself	toast.loading('…'), then update it by id
Loading → success/error tied to a promise	toast.promise(promise, { loading, success, error }) — success/error accept functions receiving the resolved value/error
Button that does something	{ action: { label, onClick } } — closes the toast unless onClick calls event.preventDefault(); cancel is the secondary variant
Custom JSX, default toast shell	toast(<jsx />)
Custom JSX, no styles at all	toast.custom((t) => <jsx />) — headless, t gives you the id to dismiss

Recipes

Update a toast — call toast() again with the same id; only the props you pass change. Switching to toast.success(…, { id }) changes the type. This is how loading → success flows work without toast.promise:

const id = toast.loading('Uploading…');
toast.success('Uploaded', { id });

Persist — { duration: Infinity }. Dismiss — toast.dismiss(id), or toast.dismiss() for all. Read active toasts — useSonner() in React, toast.getActiveToasts() outside it.

Links or components in the text — pass a function for the title or description: toast(() => <a href="…">View</a>).

Multiple toasters — give each an id and target with toast('…', { toasterId: 'canvas' }). Without toasterId, every toaster renders the toast.

Close callbacks — onDismiss fires on close button or swipe; onAutoClose fires on timeout. They are separate; there is no single "closed" callback.

Styling — the escalation ladder

Climb only as far as the change requires; jumping to the top rung too early is fine (it's the recommended end state), lingering in the middle is not.

1. Defaults — plus richColors on the Toaster for colorful success/error, invert to flip against the theme.
2. Inline tweaks — toastOptions={{ style: {…} }} on the Toaster for all toasts, or style per toast() call.
3. Classes on parts — toastOptions={{ classNames: { toast, title, description, actionButton, cancelButton, closeButton } }}. Sonner's injected styles win the cascade, so every class needs !important (Tailwind: !text-red-900). If you're marking more than a few things important, stop — go headless.
4. Headless — toast.custom() with your own JSX, keeping Sonner's positioning, stacking, and swipe. The recommended approach for a design-system toast: wrap it in your own toast() abstraction. (unstyled: true exists as a halfway house, but headless gives more control for the same effort.)

Icons — swap defaults per-type with the Toaster's icons prop, per-toast with icon, remove with null.

Theme — theme defaults to 'light' and does not track the OS. Pass theme="system", or wire your theme provider: <Toaster theme={resolvedTheme} /> from next-themes.

Troubleshooting

Symptom	Cause → fix
Toast never appears	No <Toaster /> mounted, or it unmounted (conditional render, per-page placement). Mount one at the root. If calling from a server action: toast() is client-only — call it with the action's result on the client.
Same toast appears twice	Two Toasters mounted (layout and page) — keep one. Or toast() fired in an effect under React StrictMode's dev double-invoke — fire from the event handler instead, or pass a stable id so the second call updates rather than duplicates.
Tailwind/CSS classes have no effect	Default styles override them. Mark them !important, or use unstyled / headless (see the ladder above).
Toasts render completely unstyled (common in Astro, view transitions)	Sonner's injected stylesheet was lost — import it explicitly in a layout: import 'sonner/dist/styles.css'.
Unstyled inside Shadow DOM	Styles land in document.head, not the shadow root. Copy the style tag whose text includes [data-sonner-toaster] into the shadow root.
Toast behind a modal/overlay, or clipped	An ancestor creates a stacking context (transform, filter, overflow) or the overlay out-z-indexes the toaster. Move <Toaster /> to the document root, outside any dialog/portal container.
Dark mode ignored	theme defaults to 'light' — set theme="system" or pass the resolved theme (see Theme above).
Success/error look gray, not green/red	That's the default. Add richColors to the Toaster.
Toast never closes	duration: Infinity, dismissible: false, or a toast.promise whose promise never settles — the loading toast waits forever.
toast.promise stuck on loading	It needs a promise (or a function returning one) as its first argument, and the promise must actually resolve/reject.
Swipe-to-dismiss goes the wrong way / doesn't work	Directions derive from position. Override with swipeDirections on the Toaster.
Toast shows up in every toaster	Multiple toasters need targeting: give each Toaster an id and pass toasterId in the toast() call.
Toasts too close to the screen edge on mobile	offset (desktop, default 32px) and mobileOffset (<600px, default 16px) — numbers, CSS strings, or per-side objects.