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

javascript
1// In Base44-generated apps, base44 client is pre-configured and available
2
3// CRUD operations
4const task = await base44.entities.Task.create({ title: "New task", status: "pending" });
5const tasks = await base44.entities.Task.list();
6await base44.entities.Task.update(task.id, { status: "done" });
7
8// Get current user
9const user = await base44.auth.me();

javascript
1// External apps
2import { createClient } from "@base44/sdk";
3
4// IMPORTANT: Use 'appId' (NOT 'clientId' or 'id')
5const base44 = createClient({ appId: "your-app-id" });
6await 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:

bash
1npm 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:

javascript
1import { createClient } from "@base44/sdk";
2
3// ✅ CORRECT
4const base44 = createClient({ appId: "your-app-id" });
5
6// ❌ WRONG - Do NOT use these:
7// const base44 = createClient({ clientId: "your-app-id" });  // WRONG
8// 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:

javascript
1const base44 = createClient({
2  appId: "your-app-id",
3  options: {
4    onError: (error) => {
5      console.error("Base44 error:", error);
6    }
7  }
8});

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

javascript
1const pendingTasks = await base44.entities.Task.filter(
2  { status: "pending", assignedTo: userId },  // query
3  "-created_date",                             // sort (descending)
4  10,                                          // limit
5  0                                            // skip
6);

Protected Routes (check auth)

javascript
1const user = await base44.auth.me();
2if (!user) {
3  // Navigate to your custom login page
4  navigate('/login', { state: { returnTo: window.location.pathname } });
5  return;
6}

Backend Function Call

javascript
1// Frontend
2const result = await base44.functions.invoke("processOrder", {
3  orderId: "123",
4  action: "ship"
5});
6
7// Backend function (Deno)
8import { createClientFromRequest } from "npm:@base44/sdk";
9
10Deno.serve(async (req) => {
11  const base44 = createClientFromRequest(req);
12  const { orderId, action } = await req.json();
13  // Process with service role for admin access
14  const order = await base44.asServiceRole.entities.Orders.get(orderId);
15  return Response.json({ success: true });
16});

Service Role Access

Use asServiceRole in backend functions for admin-level operations:

javascript
1// User mode - respects permissions
2const myTasks = await base44.entities.Task.list();
3
4// Service role - full access (backend only)
5const allTasks = await base44.asServiceRole.entities.Task.list();
6const token = await base44.asServiceRole.connectors.getAccessToken("slack");

Frontend vs Backend

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