Skill UI

A comprehensive guide for diagnosing and fixing common integration errors with Customer.io. It covers critical topics such as API status codes (400, 401, 429), authentication failures, incorrect timestamp formatting, and best practices for event tracking and transactional message delivery. Use this resource when troubleshooting campaign failures or API calls failing.

This skill implements core Customer.io platform features, enabling sophisticated customer communication workflows. Key functionalities include sending transactional messages (e.g., receipts, password resets) and push notifications, executing API-triggered broadcasts to defined segments, and managing user attributes to dynamically drive segment membership. Ideal for building advanced, data-driven marketing automation and customer lifecycle management systems.

This comprehensive guide demonstrates the essential workflow for integrating with Customer.io using its SDK. It covers the core functions required for user lifecycle management: identifying and updating user profiles, tracking custom events (both authenticated and anonymous), and sending transactional emails. Ideal for developers performing quick customer journey mapping or initial platform setup.

This comprehensive guide details how to install and configure the Customer.io SDK for programmatic integration in Node.js projects. It covers the critical setup of authentication using two distinct API keys: the Track API Key (for user identification and event tracking) and the App API Key (for sending transactional messages and broadcasts). Essential for developers integrating Customer.io's core customer data and marketing features.

Guides building transactional and marketing email systems that balance automation, deliverability, preference centers, and template versioning so every send hits inboxes and scales with growing infrastructure needs.

A comprehensive guide for building robust, event-driven APIs using Webhooks, Server-Sent Events (SSE), and message brokers (e.g., Kafka, RabbitMQ). This skill covers advanced patterns like the transactional outbox pattern, implementing event schemas, managing webhooks with retry logic, and establishing real-time streaming endpoints for asynchronous microservices communication. Ideal for architecting complex, scalable, and resilient systems.

Automates Postmark transactional email workflows via Rube MCP’s Composio toolkit, handling templated batch sends, template edits, delivery statistics, bounce and complaint monitoring, and server configuration while enforcing current schema discovery.

A comprehensive development tool for building and managing enterprise-grade transactional email systems. It supports modern React Email and MJML templates, generating production-ready code for major providers like Resend, Postmark, and SendGrid. Key features include multi-provider integration, internationalization (i18n), dark mode, spam score optimization, and advanced analytics tracking. Ideal for setting up new products or migrating legacy email infrastructure.

Guides building Spring Boot apps with layered architecture, REST controllers, JPA repositories, transactional services, global exception handling, DTO mappers, and testing checkpoints.

Automates Postmark transactional email operations through Rube MCP’s Composio toolkit, covering templated batch sends, template management, delivery stats, bounce handling, and server configuration with guided tool sequences and checks.

A comprehensive methodology for identifying critical vulnerabilities in transactional applications (e-commerce, fintech, SaaS). This goes beyond standard OWASP Top 10 checks, focusing on flaws like workflow bypass, state machine violations, price manipulation, and role boundary abuse. It guides testers to map application flows, identify hidden endpoints, and quantify the potential financial impact of logic failures.

A comprehensive playbook for advanced security testing, focusing on race conditions and TOCTOU (Time-of-check to time-of-use) vulnerabilities in web applications. It guides users to exploit non-atomic, state-changing operations (e.g., coupons, balance deductions, single-use rewards) by sending highly synchronized, parallel requests (including HTTP/2 single-packet attacks). Essential for identifying weaknesses in authorization and transactional integrity.