Senior Software Engineer - Messaging & AI Agent APIs Remote

CreatorIQ; Warszawa; On-site; PLN 180,000 - 240,000; Full time

Benefits offered by this job

26 days vacation

Wellness allowance

Stock options

Meal stipends

Job summary

CreatorIQ is hiring a Senior Software Engineer - Messaging & Agentic APIs in Warsaw. You will design, build, and scale backend messaging capabilities, modernize a PHP monolith into Node.js/TypeScript microservices, and create agent-ready APIs for AI integrations.

Role emphasizes secure integrations, event-driven architectures, and collaboration with Product, Design, and QA. You’ll contribute to React front-ends when needed and help improve testing, observability, and reliability across services.

Qualifications

• 5+ years of professional software engineering experience, 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 apps using React and TypeScript.
• Working knowledge of PHP, with ability to understand, troubleshoot, and safely enhance an existing legacy codebase while contributing to its modernization.
• Proven success modernizing legacy applications and decomposing monolithic architectures into microservices and serverless services.
• Experience designing 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 robust contracts and error handling.
• Strong understanding of relational databases, data modeling, and scalable backend architecture.
• Hands-on experience with OAuth 2.0, external identity providers, token management, rate limiting, retries, and resilient failure handling.
• Proficiency with AWS or similar cloud platform and event-driven architectures (Kafka, SQS, SNS, EventBridge).
• Familiarity with messaging, email, notification platforms including Google Workspace/Microsoft 365, SMTP, and related auth.
• Hands-on experience building AI-powered apps, agentic systems, or developer platforms using LLMs and OpenAPI/JSON Schema.
• Excellent problem-solving, communication, and collaboration skills; ownership from discovery to production.
• Upper-Intermediate (B2) or higher English proficiency.

Responsibilities

• Design, develop, and operate scalable backend services supporting CreatorIQ’s email and messaging capabilities.
• Understand and improve existing messaging functionality within our PHP monolith while migrating to Node.js/TypeScript microservices.
• Analyze legacy code, dependencies, and data flows to define service boundaries, APIs, data ownership, and safe migration strategies.
• Design agent-ready APIs and capabilities discoverable for AI agents and external integrations.
• Build secure integrations with Google Workspace, Microsoft 365, and other external providers.
• Develop capabilities for customer-managed inboxes, domains, sender identities, and campaign-specific messaging automation.
• Design APIs, background jobs, queues, and event-driven workflows with retries, rate limits, idempotency, and provider failures.
• Improve email authentication, deliverability, bounce/complaint processing, suppression management, and sender reputation.
• Contribute to React/TypeScript UIs for messaging config, automation, and monitoring.
• Improve automated testing, observability, performance, and reliability across legacy and new services.
• Collaborate with Product, Design, QA, DevOps, Architects, and other teams to deliver high-quality solutions.
• Review code, mentor engineers, and use AI-assisted tools to enhance engineering efficiency.

Skills

Node.js

TypeScript

React

PHP

REST/GraphQL APIs

AWS

OAuth 2.0

CI/CD

English (B2+)

JSON Schema/OpenAPI

Tools

Node.js tooling

TypeScript tooling

React

PHP monolith

AWS services

Kafka/SQS/EventBridge

Job description

CreatorIQ is hiring a Senior Software Engineer - Messaging & Agentic APIs in Warsaw. You will design, build, and scale backend messaging capabilities, modernize a PHP monolith into Node.js/TypeScript microservices, and create agent-ready APIs for AI integrations.

Role emphasizes secure integrations, event-driven architectures, and collaboration with Product, Design, and QA. You’ll contribute to React front-ends when needed and help improve testing, observability, and reliability across services.