Senior Software Engineer (Rails/LLMs)

TimeZest • Full-time • Remote • 6d ago

Company

TimeZest makes it easy for end users to schedule appointments with IT service providers. Since launching in 2019, TimeZest has grown rapidly and is now a critical piece of software used by over 1,000 businesses.

We’ve been a remote-only company from day one, with 22 great people spread across Europe, Asia, and the United States. We maintain a relaxed working environment, using just enough process to stay efficient. We’re bootstrapped, profitable, and focused on building software our customers love.

Role overview

As we expand into AI-powered features, we’re hiring a Senior Software Engineer to lead our integration of large language models (LLMs) into our platform. You’ll design and build the core backend systems that power intelligent ticket categorization, document indexing, vector search, and prompt orchestration—while helping upskill the rest of the team in this emerging space.

You’ll bring both strong Rails experience and LLM expertise, helping us build a scalable, production-grade foundation for new AI-driven capabilities.

What you’ll do

Design and build scalable backend services for LLM workflows—vector embedding, retrieval pipelines, and LLM API integration

Build data pipelines to process, index, and embed ticket content, documents, and structured data

Lead architecture decisions related to LLM orchestration, prompt engineering, context management, and API reliability

Collaborate cross-functionally with product, engineering, and design to take ideas from prototype to production

Drive backend best practices—including code quality, test coverage, observability, and performance

Mentor and guide junior and mid-level engineers through code reviews, system design sessions, and hands-on pairing

What we’re looking for

7+ years of professional software development, including 5+ years in backend roles

3+ years of recent production experience with Ruby on Rails

Strong knowledge of relational databases (PostgreSQL), data modelling, indexing, caching, and performance tuning

Track record of designing secure, scalable, observable backend systems and architectures

Hands-on experience integrating LLM APIs (e.g., OpenAI, Anthropic) into production software. Bonus if within Rails applications.

Excellent system-design skills for search & retrieval workloads, scalable services, and robust data pipelines

Excellent communication skills and the ability to mentor others in a collaborative, fully remote team

Our Stack

Ruby on Rails 7, PostgreSQL, Sidekiq, TypeScript and React, all running on Heroku.

Nice to Have

Frontend experience with TypeScript & React

Previous experience with AI/ML-focused data pipelines in other environments and languages

Experience deploying or self-hosting open-source LLMs (e.g., Mistral, LLaMA) using modern inference frameworks

Previous experience working in a remote role.

What we offer

Competitive salary with equity options

Full remote role, open worldwide providing there is some overlap with engineering team

New company issued machine

Annual company and team trips to gather and get to know each other better

Flexible hours, home-office stipend, annual learning allowance

Full licences to your favourite coding agent tool (Cursor, Copilot etc)

This is a permanent, full-time position with a salary paid monthly. It is a remote position, and you can be based anywhere in the world, if you have 2-3 hours of overlap with the engineering team.

We’re looking forward to hearing from you!