Base44 Coder

Build apps on the Base44 platform using the Base44 JavaScript SDK.

⚡ IMMEDIATE ACTION REQUIRED – Read This First

This skill activates on ANY mention of “base44” or when a base44/ folder exists. DO NOT read documentation files or search the web before acting.

Your first action MUST be:

1. Check if base44/config.jsonc exists in the current directory
2. If YES (existing project scenario):
   • This skill (base44-sdk) handles the request
   • Implement features using Base44 SDK
   • Do NOT use base44-cli unless user explicitly requests CLI commands
3. If NO (new project scenario):
   • Transfer to base44-cli skill for project initialization
   • This skill cannot help until project is initialized

When to Use This Skill vs base44-cli

Use base44-sdk when:

• Building features in an EXISTING Base44 project
• base44/config.jsonc already exists in the project
• Base44 SDK imports are present (@base44/sdk)
• Writing JavaScript/TypeScript code using Base44 SDK modules
• Implementing functionality, components, or features
• User mentions: “implement”, “build a feature”, “add functionality”, “write code for”
• User says “create a [type] app” and a Base44 project already exists

DO NOT USE base44-sdk for:

• ❌ Initializing new Base44 projects (use base44-cli instead)
• ❌ Empty directories without Base44 configuration
• ❌ When user says “create a new Base44 project/app/site” and no project exists
• ❌ CLI commands like npx base44 create, npx base44 deploy, npx base44 login (use base44-cli)

Skill Dependencies:

• base44-sdk assumes a Base44 project is already initialized
• base44-cli is a prerequisite for base44-sdk in new projects
• If user wants to “create an app” and no Base44 project exists, use base44-cli first

State Check Logic: Before selecting this skill, verify:

• IF (user mentions “create/build app” OR “make a project”):
  • IF (directory is empty OR no base44/config.jsonc exists): → Use base44-cli (project initialization needed)
  • ELSE: → Use base44-sdk (project exists, build features)

Quick Start

// In Base44-generated apps, base44 client is pre-configured and available

// CRUD operations
const task = await base44.entities.Task.create({ title: "New task", status: "pending" });
const tasks = await base44.entities.Task.list();
await base44.entities.Task.update(task.id, { status: "done" });

// Get current user
const user = await base44.auth.me();

// External apps
import { createClient } from "@base44/sdk";

// IMPORTANT: Use 'appId' (NOT 'clientId' or 'id')
const base44 = createClient({ appId: "your-app-id" });
await base44.auth.loginViaEmailPassword("user@example.com", "password");

⚠️ CRITICAL: Do Not Hallucinate APIs

Before writing ANY Base44 code, verify method names against this table or QUICK_REFERENCE.md.

Base44 SDK has unique method names. Do NOT assume patterns from Firebase, Supabase, or other SDKs.

Authentication – WRONG vs CORRECT

Functions – WRONG vs CORRECT

Integrations – WRONG vs CORRECT

Entities – WRONG vs CORRECT

SDK Modules

For client setup and authentication modes, see client.md.

TypeScript Support: Each reference file includes a “Type Definitions” section with TypeScript interfaces and types for the module’s methods, parameters, and return values.

Installation

Install the Base44 SDK:

npm install @base44/sdk

Important: Never assume or hardcode the @base44/sdk package version. Always install without a version specifier to get the latest version.

Creating a Client (External Apps)

When creating a client in external apps, ALWAYS use appId as the parameter name:

import { createClient } from "@base44/sdk";

// ✅ CORRECT
const base44 = createClient({ appId: "your-app-id" });

// ❌ WRONG - Do NOT use these:
// const base44 = createClient({ clientId: "your-app-id" });  // WRONG
// const base44 = createClient({ id: "your-app-id" });        // WRONG

Required parameter: appId (string) – Your Base44 application ID

Optional parameters:

• token (string) – Pre-authenticated user token
• options (object) – Configuration options
  • options.onError (function) – Global error handler

Example with error handler:

const base44 = createClient({
  appId: "your-app-id",
  options: {
    onError: (error) => {
      console.error("Base44 error:", error);
    }
  }
});

Module Selection

Working with app data?

• Create/read/update/delete records → entities
• Import data from file → entities.importEntities()
• Realtime updates → entities.EntityName.subscribe()

User management?

• Login/register/logout → auth
• Get current user → auth.me()
• Update user profile → auth.updateMe()
• Invite users → users.inviteUser()

AI features?

• Chat with AI agents → agents (requires logged-in user)
• Create new conversation → agents.createConversation()
• Manage conversations → agents.getConversations()
• Generate text/JSON with AI → integrations.Core.InvokeLLM()
• Generate images → integrations.Core.GenerateImage()

Custom backend logic?

• Run server-side code → functions.invoke()
• Need admin access → base44.asServiceRole.functions.invoke()

External services?

• Send emails → integrations.Core.SendEmail()
• Upload files → integrations.Core.UploadFile()
• Custom APIs → integrations.custom.call()
• OAuth tokens (Google, Slack) → connectors (backend only)

Tracking and analytics?

• Track custom events → analytics.track()
• Log page views/activity → appLogs.logUserInApp()

Common Patterns

Filter and Sort Data

const pendingTasks = await base44.entities.Task.filter(
  { status: "pending", assignedTo: userId },  // query
  "-created_date",                             // sort (descending)
  10,                                          // limit
  0                                            // skip
);

Protected Routes (check auth)

const user = await base44.auth.me();
if (!user) {
  // Navigate to your custom login page
  navigate('/login', { state: { returnTo: window.location.pathname } });
  return;
}

Backend Function Call

// Frontend
const result = await base44.functions.invoke("processOrder", {
  orderId: "123",
  action: "ship"
});

// Backend function (Deno)
import { createClientFromRequest } from "npm:@base44/sdk";

Deno.serve(async (req) => {
  const base44 = createClientFromRequest(req);
  const { orderId, action } = await req.json();
  // Process with service role for admin access
  const order = await base44.asServiceRole.entities.Orders.get(orderId);
  return Response.json({ success: true });
});

Service Role Access

Use asServiceRole in backend functions for admin-level operations:

// User mode - respects permissions
const myTasks = await base44.entities.Task.list();

// Service role - full access (backend only)
const allTasks = await base44.asServiceRole.entities.Task.list();
const token = await base44.asServiceRole.connectors.getAccessToken("slack");

Frontend vs Backend

Backend functions use Deno.serve() and createClientFromRequest(req) to get a properly authenticated client.