Senior Backend Engineer

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.

About the Role

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, ; 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)

What You'll Bring

• 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

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

Role Details

• Start Date: Immediately

• Status: Full-time (40 hours/week)

• Type: Hybrid (3 days/week in-office)

• Location: Barcelona, Spain

• Travel: Annual company offsite in Seattle. Occasional travel to Spain and Budapest possible.

• Department: Product

• Reports to: Director of Product

• Direct Reports: None

Why Join Hiya?

We're building a team with diverse perspectives and backgrounds. Diversity and unique viewpoints make us stronger and more dynamic. We've won awards from Built In Seattle, Seattle Business Week, Deloitte Technology Fast 500, and Forbes' #1 Startup Employer. At Hiya, you'll find a supportive, empowering culture that encourages innovation and personal growth. If you want to help disrupt an industry and make a tangible impact, join us