Convex is the typesafe backend-as-a-service with realtime updates, server functions, crons and scheduled jobs, file storage, vector search, and more.

Quickstart

Receive live updates to Convex query subscriptions and call mutations and actions from Svelte with convex-svelte.

To install:

npm install convex convex-svelte

Run npx convex init to get started with Convex.

See the example app live.

convex-svelte provides a setupConvex() function which takes a Convex deployment URL, a useConvexClient() which returns a ConvexClient used to set authentication credentials and run Convex mutations and actions, and a useQuery() function for subscribing to Convex queries.

Call setupConvex() in a component above the components that need to Convex queries and use useQuery() components where you need to listen to the query.

See +layout.svelte for setupConvex()

<script>
	import { PUBLIC_CONVEX_URL } from '$env/static/public';

	setupConvex(PUBLIC_CONVEX_URL);
</script>

and Chat.svelte for how to use useQuery()

<script>
	const query = useQuery(api.messages.list, () => ({ muteWords }), {
		useResultFromPreviousArguments: true
	});
</script>

...
{#if query.isLoading}
	Loading...
{:else if query.error != null}
	failed to load: {query.error.toString()}
{:else}
	<ul>
		{#each query.data as message}
			<li>
				<span>{message.author}</span>
				<span>{message.body}</span>
			</li>
		{/each}
	</ul>
{/if}

Running a mutation looks like

<script>
	const client = useConvexClient();

	let toSend = $state('');
	let author = $state('me');

	function onSubmit(e: SubmitEvent) {
		const data = Object.fromEntries(new FormData(e.target as HTMLFormElement).entries());
		client.mutation(api.messages.send, {
			author: data.author as string,
			body: data.body as string
		});
	}
</script>

<form on:submit|preventDefault={onSubmit}>
	<input type="text" id="author" name="author" />
	<input type="text" id="body" name="body" bind:value={toSend} />
	<button type="submit" disabled={!toSend}>Send</button>
</form>

In production build pipelines use the build command

npx convex deploy --cmd-url-env-var-name PUBLIC_CONVEX_URL --cmd 'npm run build'

to build your Svelte app and deploy Convex functions.

Clone this repo and install dependencies with npm install then start a development server:

npm run dev

This will run you through creating a Convex account and a deployment.

Everything inside src/lib is part of the library, everything inside src/routes is an example app.

To build the library:

npm run package

To create a production version of the showcase app:

npm run build

You can preview the production build with npm run preview.

To deploy your app, you may need to install an adapter for your target environment.

Go into the package.json and give your package the desired name through the "name" option. Also consider adding a "license" field and point it to a LICENSE file which you can create from a template (one popular option is the MIT license).

To publish your library to npm:

npm publish