Best Backend for React Apps in 2025

import { createClient } from '@supabase/supabase-js'
import { useEffect, useState } from 'react'

const supabase = createClient('YOUR_URL', 'YOUR_KEY')

function App() {
  const [todos, setTodos] = useState([])

  useEffect(() => {
    // Fetch data
    fetchTodos()

    // Subscribe to real-time changes
    const subscription = supabase
      .channel('todos')
      .on('postgres_changes',
        { event: '*', schema: 'public', table: 'todos' },
        () => fetchTodos()
      )
      .subscribe()

    return () => subscription.unsubscribe()
  }, [])

  async function fetchTodos() {
    const { data } = await supabase
      .from('todos')
      .select('*')
    setTodos(data)
  }

  return <div>{/* Render todos */}</div>
}

import { useQuery, useMutation } from "convex/react"
import { api } from "../convex/_generated/api"

function App() {
  // Automatically reactive - updates when data changes
  const todos = useQuery(api.todos.list)
  const addTodo = useMutation(api.todos.add)

  async function handleAdd(text) {
    await addTodo({ text })
    // UI updates automatically!
  }

  return <div>{/* Render todos */}</div>
}

// That's it! Real-time with zero config.