Next.js + Vercel Firewall - Rate Limit

safe-actions.ts

import { unstable_checkRateLimit as checkRateLimit } from '@vercel/firewall'
import { DEFAULT_SERVER_ERROR_MESSAGE, createSafeActionClient,} from 'next-safe-action'
import { headers } from 'next/headers'

// Creating an action client using the createSafeActionClient function
export const actionClient = createSafeActionClient({
	// Handling returned server errors
	handleReturnedServerError(e) {
		// If the error is an instance of Error, return its message
		if (e instanceof Error) {
			return e.message
		}
		// Otherwise, return the default server error message
		return DEFAULT_SERVER_ERROR_MESSAGE
	},
}).use(async ({ next }) => {
	// Checking the rate limit using the checkRateLimit function
	const { rateLimited, error } = await checkRateLimit('my-rate-limit-id', {
		// Passing the headers to the checkRateLimit function
		headers: headers(),
	})

	// If the rate limit is exceeded, throw an error
	if (rateLimited) {
		throw new Error('Too many requests')
	}

	// Proceed to the next middleware or handler with the rate limit error in the context
	return next({
		ctx: {
			ratelimit: {
				error,
			},
		},
	})
})

Create the rule in Vercel Firewall & copy the rate limit ID you get, then you can use it to checkRateLimit.