# Customjs

```json
{
  "name": "Customjs",
  "slug": "customjs",
  "url": "https://composio.dev/toolkits/customjs",
  "markdown_url": "https://composio.dev/toolkits/customjs.md",
  "logo_url": "https://logos.composio.dev/api/customjs",
  "categories": [
    "developer tools & devops"
  ],
  "is_composio_managed": false,
  "updated_at": "2026-05-12T10:08:04.911Z"
}
```

![Customjs logo](https://logos.composio.dev/api/customjs)

## Description

Securely connect your AI agents and chatbots (Claude, ChatGPT, Cursor, etc) with Customjs MCP or direct API to run custom JavaScript automations, generate dynamic PDFs, send transactional emails, and update CRM fields through natural language.

## Summary

Customjs is a code-first automation platform for integrating custom JavaScript logic across your tech stack. It lets you extend applications quickly by writing functions for tasks like emails, PDFs, or CRM updates.

## Categories

- developer tools & devops

## Toolkit Details

- Tools: 5

## Images

- Logo: https://logos.composio.dev/api/customjs

## Authentication

- **Api Key**
  - Type: `api_key`
  - Description: Api Key authentication for Customjs.
  - Setup:
    - Configure Api Key credentials for Customjs.
    - Use the credentials when creating an auth config in Composio.

## Suggested Prompts

- Convert this HTML invoice to PDF file
- Take a screenshot of my company homepage
- Merge these three PDF reports into one
- Run Puppeteer script to extract table data

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `CUSTOMJS_AUTHENTICATE_API_KEY` | Authenticate CustomJS API Key | Authenticate and validate a CustomJS API key. Returns workspace details, request limits, and decoded JWT token information including user email. Use this to verify an API key is valid before making other CustomJS API calls. |
| `CUSTOMJS_CONVERT_HTML_TO_PDF` | Convert HTML to PDF | Convert HTML content to a PDF document. Use this tool to generate PDF files from raw HTML markup. Supports: - Complete HTML documents or fragments - Inline CSS styling (colors, fonts, tables, borders, backgrounds) - Unicode characters and special symbols - Multi-page documents Returns raw PDF bytes suitable for file storage or download. |
| `CUSTOMJS_CONVERT_HTML_TO_PNG` | Convert HTML to PNG | Tool to convert HTML string to PNG image. Use when you need a PNG from HTML after preparing your markup. |
| `CUSTOMJS_MERGE_PDFS` | Merge multiple PDFs into one | Merge multiple PDF files from URLs into a single PDF document. Use this tool when you need to combine two or more PDF documents into one. The PDFs are merged in the order provided. All input URLs must be publicly accessible. Returns a downloadable merged PDF file. |
| `CUSTOMJS_RUN_PUPPETEER_SCRIPT` | Run Puppeteer Script | Execute a Puppeteer script in a headless browser and capture a screenshot. Use this tool for browser automation tasks such as navigating to URLs, interacting with page elements, extracting data, or capturing visual snapshots of web pages. The script runs in a sandboxed Puppeteer environment with access to a 'page' object. |

## Supported Triggers

None listed.

## Installation and MCP Setup

### Path 1: SDK Installation

#### Path 1, Step 1: Install Composio

Install the Composio SDK
```python
pip install composio_openai
```

```typescript
npm install @composio/openai
```

#### Path 1, Step 2: Initialize Composio and Create Tool Router Session

Import and initialize Composio client, then create a Tool Router session
```python
from openai import OpenAI
from composio import Composio
from composio_openai import OpenAIResponsesProvider

composio = Composio(provider=OpenAIResponsesProvider())
openai = OpenAI()
session = composio.create(user_id='your-user-id')
```

```typescript
import OpenAI from 'openai';
import { Composio } from '@composio/core';
import { OpenAIResponsesProvider } from '@composio/openai';

const composio = new Composio({
  provider: new OpenAIResponsesProvider(),
});
const openai = new OpenAI({});
const session = await composio.create('your-user-id');
```

#### Path 1, Step 3: Execute Customjs Tools via Tool Router with Your Agent

Get tools from Tool Router session and execute Customjs actions with your Agent
```python
tools = session.tools
response = openai.responses.create(
  model='gpt-4.1',
  tools=tools,
  input=[{
    'role': 'user',
    'content': 'Convert this HTML invoice to a PDF file.'
  }]
)
result = composio.provider.handle_tool_calls(
  response=response,
  user_id='your-user-id'
)
print(result)
```

```typescript
const tools = session.tools;
const response = await openai.responses.create({
  model: 'gpt-4.1',
  tools: tools,
  input: [{
    role: 'user',
    content: 'Convert this HTML invoice to a PDF file.'
  }],
});
const result = await composio.provider.handleToolCalls(
  'your-user-id',
  response.output
);
console.log(result);
```

### Path 2: MCP Server Setup

#### Path 2, Step 1: Install Composio

Install the Composio SDK and Claude Agent SDK
```python
pip install composio claude-agent-sdk
```

```typescript
npm install @composio/core ai @ai-sdk/openai @ai-sdk/mcp
```

#### Path 2, Step 2: Create Tool Router Session

Initialize the Composio client and create a Tool Router session
```python
from composio import Composio
from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions

composio = Composio(api_key='your-composio-api-key')
session = composio.create(user_id='your-user-id')
url = session.mcp.url
```

```typescript
import { Composio } from '@composio/core';

const composio = new Composio({ apiKey: 'your-api-key' });

console.log("Creating Tool Router session...");
const { mcp } = await composio.create('your-user-id');
console.log(`Tool Router session created: ${mcp.url}`);
```

#### Path 2, Step 3: Connect to AI Agent

Use the MCP server with your AI agent
```python
import asyncio

options = ClaudeAgentOptions(
    permission_mode='bypassPermissions',
    mcp_servers={
        'tool_router': {
            'type': 'http',
            'url': url,
            'headers': {
                'x-api-key': 'your-composio-api-key'
            }
        }
    },
    system_prompt='You are a helpful assistant with access to Customjs tools.',
    max_turns=10
)

async def main():
    async with ClaudeSDKClient(options=options) as client:
        await client.query('Convert this HTML string to a PDF')
        async for message in client.receive_response():
            if hasattr(message, 'content'):
                for block in message.content:
                    if hasattr(block, 'text'):
                        print(block.text)

asyncio.run(main())
```

```typescript
import { openai } from '@ai-sdk/openai';
import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';
import { generateText, stepCountIs } from 'ai';

const client = await createMCPClient({
  transport: {
    type: 'http',
    url: mcp.url,
    headers: { 'x-api-key': 'your-composio-api-key' }
  }
});

const tools = await client.tools();

const { text } = await generateText({
  model: openai('gpt-4o'),
  tools,
  messages: [{ role: 'user', content: 'Convert this HTML string to a PDF' }],
  stopWhen: stepCountIs( 5 )
});

console.log(`Agent: ${text}`);
```

## Why Use Composio?

### 1. AI Native Customjs Integration

- Supports both Customjs MCP and direct API based integrations
- Structured, LLM-friendly schemas for reliable tool execution
- Rich coverage for reading, writing, and querying your Customjs data

### 2. Managed Auth

- Built-in OAuth handling with automatic token refresh and rotation
- Central place to manage, scope, and revoke Customjs access
- Per user and per environment credentials instead of hard-coded keys

### 3. Agent Optimized Design

- Tools are tuned using real error and success rates to improve reliability over time
- Comprehensive execution logs so you always know what ran, when, and on whose behalf

### 4. Enterprise Grade Security

- Fine-grained RBAC so you control which agents and users can access Customjs
- Scoped, least privilege access to Customjs resources
- Full audit trail of agent actions to support review and compliance

## Use Customjs with any AI Agent Framework

Choose a framework you want to connect Customjs with:

- [OpenAI Agents SDK](https://composio.dev/toolkits/customjs/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/customjs/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/customjs/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/customjs/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/customjs/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/customjs/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/customjs/framework/hermes-agent)
- [Google ADK](https://composio.dev/toolkits/customjs/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/customjs/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/customjs/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/customjs/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/customjs/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/customjs/framework/crew-ai)
- [Pydantic AI](https://composio.dev/toolkits/customjs/framework/pydantic-ai)
- [AutoGen](https://composio.dev/toolkits/customjs/framework/autogen)

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## Frequently Asked Questions

### Do I need my own developer credentials to use Customjs with Composio?

Yes, Customjs requires you to configure your own API key credentials. Once set up, Composio handles secure credential storage and API request handling for you.

### Can I use multiple toolkits together?

Yes! Composio's Tool Router enables agents to use multiple toolkits. [Learn more](https://docs.composio.dev/tool-router/overview).

### Is Composio secure?

Composio is SOC 2 and ISO 27001 compliant with all data encrypted in transit and at rest. [Learn more](https://trust.composio.dev).

### What if the API changes?

Composio maintains and updates all toolkit integrations automatically, so your agents always work with the latest API versions.

---
[See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)