Sinch
Sinch
Sinch provides communications software and infrastructure for businesses and communication providers. Its CPaaS platform combines developer-focused APIs and applications for messaging, voice, email, identity verification, and conversational AI with network connectivity and telco services. Organizations use Sinch to deliver marketing campaigns, notifications, alerts, customer support, and verification flows across channels including SMS, RCS, WhatsApp, email, and voice. The company’s platform is built around scalable communications infrastructure and extensive operator connectivity.

Senior Software Engineer, Conversational AI Platform (Madrid Hybrid)

Build scalable backend services for Sinch’s conversational AI platform, supporting real-time text and voice interactions. Work across distributed systems, integrations, and cloud infrastructure.

Description

  • Build backend services for Chatlayer’s text and voice channels, including WebSocket servers and real-time communication infrastructure.
  • Develop platform integrations and application-integration frameworks.
  • Help modernize the architecture by removing legacy dependencies and creating modular, vendor-agnostic systems.
  • Contribute to technical decisions involving SinchID, MongoDB Atlas, Kafka, Temporal, and emerging platform capabilities.
  • Lead code reviews, technical discussions, and knowledge-sharing sessions.
  • Mentor engineers, seek mentorship, and help strengthen the engineering culture.
  • Support production systems through on-call rotations and incident response.
  • Expand test coverage, reduce technical debt, and improve operational processes.

Requirements

  • At least five years of professional software engineering experience.
  • Strong proficiency with Node.js and TypeScript, Go, or both.
  • Experience developing real-time systems, including WebSocket or event-driven architectures.
  • Hands-on experience with complex cloud infrastructure, preferably GCP and/or AWS.
  • Experience with microservices and distributed systems, including state management across replicas using technologies such as ETCD or Redis.
  • Working knowledge of MongoDB or a comparable document database.
  • Experience building and maintaining RESTful APIs and event-driven architectures, preferably with Kafka.
  • Strong system design fundamentals, including scalability, latency, failover, and architectural trade-offs.
  • Excellent communication skills and confidence working with distributed, cross-functional teams.
  • English is the corporate language, and applications must be submitted in English.
  • Preferred: experience with conversational AI, chatbot or voicebot platforms, or NLP/NLU pipelines.
  • Preferred: experience using Docker and Kubernetes.
  • Preferred: familiarity with OAuth/OIDC identity management systems.
  • Preferred: previous experience in a CPaaS, scale-up, or fast-growth product company.

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