Senior Backend Engineer - AI

Hiya
Barcelona, Spain
10 days ago

Role details

Contract type
Permanent contract
Employment type
Full-time (> 32 hours)
Working hours
Regular working hours
Languages
English
Experience level
Senior

Job location

Barcelona, Spain

Tech stack

A/B testing
API
Artificial Intelligence
User Authentication
VoIP
Software as a Service
Cloud Computing
Databases
PostgreSQL
Node.js
Data Streaming
TypeScript
Web Applications
Google Cloud Platform
React
Large Language Models
Prompt Engineering
Deep Learning
Audio Streaming
Backend
Kubernetes
REST
GPT
Docker
Crud
Microservices

Job description

As a Senior Engineer within our Audio Intelligence team, you'll help build leading-edge audio and speech solutions leveraging AI and Deep Learning. Our products range from AI Voice Deepfake Detection, Voice Authentication, and Voice AI Agents-delivered either via APIs for developer use or as part of a no-code SaaS platform.

You'll be an individual contributor (IC) focused on evolving our SaaS architecture: REST APIs, web consoles, demos, and integrations. You'll help design new services and flows involving CRUD operations, audio streaming, and AI model inference.

While backend-focused, you'll work closely with R&D and Product teams to integrate and experiment with AI models, including designing prompts, consuming external model APIs, and building model-in-the-loop systems. What You'll Do

  • Build and maintain REST/gRPC backend services (TypeScript, Node.js; Rust a plus)
  • Build web applications and agent interfaces using React or SvelteKit
  • Integrate LLMs via APIs (prompt engineering, tool calling, RAG)
  • Manage Postgres-backed databases and deployments with Docker/Kubernetes (GCP)

Requirements

  • 4+ years of backend or full-stack engineering experience
  • Experience (or strong interest) in applied AI: using LLMs, building agents, or integrating model APIs
  • Strong product sense and ownership
  • Comfort in a fast-paced, customer-facing environment
  • Familiarity with cloud infrastructure (ideally GCP) and CI/CD pipelines
  • Desire to use AI tools to improve development speed and quality
  • Excellent communication and self-organization skills, including remote teamwork

Bonus Points

  • Experience with agentic workflows (OpenAI, Anthropic, or similar APIs)
  • Experience with streaming APIs, media pipelines, or voice AI platforms
  • Knowledge of telephony protocols (SIP, VoIP)
  • LLM evaluation techniques (A/B tests, GPT-judge, synthetic data)
  • Interest in conversational UX or real-time AI applications

You'll hit the ground running if you have experience with:

  • Rust, TypeScript
  • GCP, Kubernetes, Postgres
  • LLMs via API, prompt engineering, RAG, or orchestrating model pipelines

Benefits & conditions

Don't meet every single requirement? If your skills are transferable, we still want to hear from you.

About the company

About Hiya Hiya is revolutionizing voice communication. Our mission: modernize voice with intelligence for security and productivity. Since launching the first mobile caller ID and spam-blocking apps in 2015, we've led voice intelligence innovation. We partnered with Samsung and AT&T in 2016 to launch Hiya Protect, the first network-based spam-blocking solution, and introduced Hiya Connect in 2019-a branded call SaaS platform empowering businesses to reach more customers by phone. Today, our Voice Intelligence Platform supports over 500 million users globally, leveraging adaptive AI and audio intelligence for smarter, safer, and more productive voice calls across networks, apps, and devices. Our partners include British Telecom, EE, Virgin Media O2, Ericsson, Rogers, Bell Canada, MasMovil, Telenor, FICO, Twilio, and more.

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