base44-sdk

SKILL.md

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:

Check if base44/config.jsonc exists in the current directory

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

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

❌ WRONG (hallucinated)
✅ CORRECT

signInWithGoogle()
loginWithProvider('google')

signInWithProvider('google')
loginWithProvider('google')

auth.google()
loginWithProvider('google')

signInWithEmailAndPassword(email, pw)
loginViaEmailPassword(email, pw)

signIn(email, pw)
loginViaEmailPassword(email, pw)

createUser() / signUp()
register({email, password})

onAuthStateChanged()
me() (no listener, call when needed)

currentUser
await auth.me()

Functions - WRONG vs CORRECT

❌ WRONG (hallucinated)
✅ CORRECT

functions.call('name', data)
functions.invoke('name', data)

functions.run('name', data)
functions.invoke('name', data)

callFunction('name', data)
functions.invoke('name', data)

httpsCallable('name')(data)
functions.invoke('name', data)

Integrations - WRONG vs CORRECT

❌ WRONG (hallucinated)
✅ CORRECT

ai.generate(prompt)
integrations.Core.InvokeLLM({prompt})

openai.chat(prompt)
integrations.Core.InvokeLLM({prompt})

llm(prompt)
integrations.Core.InvokeLLM({prompt})

sendEmail(to, subject, body)
integrations.Core.SendEmail({to, subject, body})

email.send()
integrations.Core.SendEmail({to, subject, body})

uploadFile(file)
integrations.Core.UploadFile({file})

storage.upload(file)
integrations.Core.UploadFile({file})

Exception: an OpenAI-compatible client (e.g. the Vercel AI SDK) is correct when pointed at base44.aiGateway.connection() — that's how you build code agents (agent loops with tools). Use InvokeLLM only for a single call with no tools. See ai-gateway.md.

Entities - WRONG vs CORRECT

❌ WRONG (hallucinated)
✅ CORRECT

entities.Task.find({...})
entities.Task.filter({...})

entities.Task.findOne(id)
entities.Task.get(id)

entities.Task.insert(data)
entities.Task.create(data)

entities.Task.remove(id)
entities.Task.delete(id)

entities.Task.onChange(cb)
entities.Task.subscribe(cb)

SDK Modules

Module
Purpose
Reference

entities
CRUD operations on data models
entities.md

auth
Login, register, user management
auth.md

agents
AI conversations and messages
base44-agents.md

functions
Backend function invocation
functions.md

integrations
AI, email, file uploads, custom APIs
integrations.md

aiGateway
Connect an OpenAI-compatible SDK to Base44's AI gateway
ai-gateway.md

analytics
Track custom events and user activity
analytics.md

appLogs
Log user activity in app
app-logs.md

users
Invite users to the app
users.md

asServiceRole.connectors
App-scoped OAuth tokens (service role only)
connectors.md

asServiceRole.sso
SSO token generation (service role only)
sso.md

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

TypeScript and type registries

Each reference file includes a "Type Definitions" section with TypeScript interfaces and types for the module's methods, parameters, and return values.

Getting typed entities, functions, and agents: The Base44 CLI generates types from your project resources (entities, functions, agents), including augmentations to EntityTypeRegistry, FunctionNameRegistry, and AgentNameRegistry, and wires them into your project so you get autocomplete and type checking without manual setup. For how to generate types, use the base44-cli skill.

Manual augmentation: You can instead augment the registries yourself in a .d.ts file; see the Type Definitions sections in entities.md, functions.md, and base44-agents.md.

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()

Build a custom agent with tools (backend, agent SDK on the AI gateway) → aiGateway (see ai-gateway.md)

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()

App-scoped OAuth (app builder's account) → asServiceRole.connectors.getConnection() (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
// ⚠️ invoke() returns the RAW axios response — your function's JSON is on `.data`,
//    NOT the top-level object. It also THROWS on non-2xx (error body at err.response.data).
const res = await base44.functions.invoke("processOrder", {
  orderId: "123",
  action: "ship"
});
const result = res.data; // ✅ e.g. res.data.success  (res itself is { data, status, headers, … })

// 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

Capability
Frontend
Backend

entities (user's data)
Yes
Yes

auth
Yes
Yes

agents
Yes
Yes

functions.invoke()
Yes
Yes

functions.fetch()
Yes
Yes

integrations
Yes
Yes

aiGateway
No
Yes

analytics
Yes
Yes

appLogs
Yes
Yes

users
Yes
Yes

asServiceRole.*
No
Yes

asServiceRole.connectors (app OAuth)
No
Yes

asServiceRole.sso
No
Yes

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