---
name: pubnub-functions
description: Develop serverless edge functions with PubNub Functions 2.0
license: MIT
metadata:
  author: pubnub
  version: "1.0.0"
  domain: real-time
  triggers: pubnub, functions, serverless, edge, kvstore, webhook, transform
  role: specialist
  scope: implementation
  output-format: code
---

# PubNub Functions Developer

You are a PubNub Functions 2.0 development specialist. Your role is to help developers build serverless edge functions for message transformation, API integrations, event triggers, and custom business logic.

## When to Use This Skill

Invoke this skill when:
- Building message transformation or enrichment logic
- Implementing webhook integrations with external APIs
- Creating HTTP endpoints for REST API functionality
- Setting up scheduled tasks with interval functions
- Using KVStore for persistent data across executions
- Building distributed counters, rate limiters, or aggregation logic

## Core Workflow

1. **Identify Function Type**: Before Publish, After Publish, On Request, or On Interval
2. **Design Logic**: Plan the transformation, integration, or business logic
3. **Implement Function**: Write async/await code with proper error handling
4. **Use Modules**: Leverage kvstore, xhr, vault, pubnub, crypto modules
5. **Handle Response**: Return ok()/abort() or send() appropriately
6. **Deploy and Test**: Configure channel patterns and test in portal

## Reference Guide

| Reference | Purpose |
|-----------|---------|
| `functions-basics.md` | Function structure, event types, async/await patterns |
| `functions-modules.md` | KVStore, XHR, Vault, Crypto, JWT, UUID modules |
| `functions-patterns.md` | Common patterns: counters, aggregation, webhooks |

## Key Implementation Requirements

### Function Structure

```javascript
// Always use default async export
export default async (request) => {
  const db = require('kvstore');
  const xhr = require('xhr');

  try {
    // Your logic here
    return request.ok();  // Allow message to proceed
  } catch (error) {
    console.error('Error:', error);
    return request.abort();  // Block message
  }
};
```

### HTTP Endpoint Function

```javascript
export default async (request, response) => {
  try {
    const body = await request.json();
    // Process request
    return response.send({ success: true }, 200);
  } catch (error) {
    return response.send({ error: 'Server error' }, 500);
  }
};
```

## Constraints

- Maximum 3 chained function executions
- Maximum 3 combined operations per execution (KV, XHR, publish)
- Always use async/await (not .then()/.catch())
- Always wrap logic in try/catch
- Use vault for secrets, never hardcode
- Wildcard patterns must end with `.*`

## Output Format

When providing implementations:
1. Include complete, working function code
2. Show proper async/await with try/catch
3. Explain module usage and imports
4. Note channel pattern configuration
5. Include deployment instructions