Senior Software Engineer - Messaging & Agentic APIs
$299,000–$375,000 year
HybridWarsaw, Mazovia, Poland
Job Summary
Design, develop, and operate scalable backend services for CreatorIQ's messaging and agentic API platform, focusing on Node.js and TypeScript while maintaining legacy PHP monolith functionality. Build agent-ready APIs, secure integrations with Google Workspace and Microsoft 365, and implement reliable message delivery at scale using event-driven architectures and queues. Contribute to React and TypeScript front-end development for configuration and monitoring interfaces, while improving automated testing, observability, and performance across the system. Collaborate with Product, Design, and DevOps teams to modernize the messaging architecture and deliver high-quality end-to-end solutions.
Required Qualifications
- 5+ years of professional software engineering experience, including ownership of complex production systems from design through deployment
- Strong backend development skills with Node.js and TypeScript, complemented by the ability to build customer-facing applications using React and TypeScript
- Working knowledge of PHP, with the ability to understand, troubleshoot, and safely enhance an existing legacy codebase while contributing to its modernization
- Proven success modernizing legacy applications and incrementally decomposing monolithic architectures into microservices and serverless services
- Expertise in designing and building REST and/or GraphQL APIs, third-party integrations, and asynchronous processing workflows
- Ability to design APIs for machine-to-machine communication, AI agents, or automated workflows with well-defined contracts, structured schemas, predictable behavior, and robust error handling
- Strong understanding of relational databases, data modeling, transactions, query optimization, and scalable backend architecture
- Hands-on experience implementing secure integrations using OAuth 2.0, external identity providers, token management, rate limiting, retries, and resilient failure handling
- Proficiency with AWS or another major cloud platform, including event-driven architectures using technologies such as Kafka, Amazon SQS, SNS, or EventBridge
- Familiarity with messaging, email, notification, or communication platforms, including business inboxes, messaging automation, and campaign workflows
- Knowledge of messaging and email technologies such as Google Workspace/Gmail APIs, Microsoft Graph/Outlook 365, SMTP, Amazon SES, SPF, DKIM, and DMARC
- Hands-on experience building AI-powered applications, agentic systems, or developer platforms using LLMs, AI agents, copilots, or workflow orchestration frameworks, with strong knowledge of JSON Schema, OpenAPI, function calling, and Model Context Protocol (MCP) or similar standards
- Solid understanding of automated testing, CI/CD pipelines, observability, monitoring, and production support best practices
- Excellent problem-solving, communication, and collaboration skills, with the ability to independently own features from technical discovery through production rollout
- Upper-Intermediate (B2) or higher English proficiency, both written and spoken
Desired Qualifications
- Experience developing messaging automation, sequencing, scheduling, or campaign orchestration capabilities is a plus
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