Backend Engineer - AI Agents (all genders)

Lime Connect (ehemals Userlike); Köln; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Health budget

Urban Sports Club membership

Learning budget

Udemy access

Leadership programmes

28 days holiday

Job summary

Lime Connect, an AI-first software scale-up in Cologne, seeks a backend engineer responsible for advancing AI agents and automation, collaborating closely with Product. You’ll shape AI architecture to flexibly work with different LLMs and improve agent performance through real-customer evals and observability tools.

Office in Cologne with 3 days on-site and 2 days remote. The role requires 5+ years in backend and hands-on AI feature development, with Python and ideally TypeScript.

Qualifications

• Five+ years of backend experience.
• Experience building AI features based on language models.

Responsibilities

• Develop AI agents and automation solutions (Connect AI).
• Shape AI architecture for multi-LLM workflows.
• Ensure quality with evals on real customer conversations and LLM-as-a-judge.
• Integrate knowledge/tools via APIs, MCP tools, and crawlers.

Skills

Backend experience

Python

TypeScript

AI agents

Context windows

Tool calling

Pydantic AI

RAG

Vector databases

Langfuse/Arize Phoenix

German & English

Job description

What You’ll Be Working On

• Within the backend team, you’re the go-to person for AI and work closely with Product.
• You further develop our AI agents and automation solutions such as Connect AI, from the agent loop and tool calling to context management.
• You help shape our AI architecture and make sure we can work flexibly with different LLMs.
• When it comes to quality, we rely on evals with real customer conversations and methods like LLM-as-a-judge. You help expand this area so every new version gets measurably better.
• Through APIs, MCP tools and website crawling, you give our agents the knowledge and tools they need.

What Makes You a Fit

• You have at least five years of backend experience, including one year building AI features based on language models that people use every day.
• You know Python and ideally TypeScript.
• You’ve built AI agents before and know context windows, tool calling and prompting from hands‑on work. Agent libraries like Pydantic AI might already be part of your toolkit.
• You’ve worked with RAG and vector databases yourself. Evals and observability are familiar ground for you, whether with Langfuse, Arize Phoenix or a setup you built yourself.
• Experience with AI gateways like Bifrost or LiteLLM is a nice extra.
• You follow what’s happening in AI, try things out quickly and take ownership of your topics.
• You’re fluent in German and English.

What’s In It For You

HEALTH & SPORTS

• 600 € health budget per year, including 24/7 medical advice — also for family members in your household
• Subsidised Urban Sports Club membership (20 € monthly contribution)

DEVELOPMENT & GROWTH

• Learning budget for courses, books and conferences
• Free access to Udemy, Masterclass and language learning apps
• Leadership programmes such as "Next Gen" and "Effective Manager"

TEAM & CULTURE

• Weekly FIKA, movie nights, book club and regular get-togethers and team events
• International summer party together with our colleagues in the Nordics

WORK ENVIRONMENT

• Office-first setup: 3 days in our Cologne office at the MediaPark, 2 days remote
• 360° view across Cologne from the 14th floor
• Workation within the EU
• Snacks, cereal bar and drinks in the office

COMPENSATION & BENEFITS

• Company pension scheme via Zurich with a 30 % employer contribution
• Job ticket or mobility budget, plus free parking at the MediaPark
• Corporate benefits
• 28 days of holiday, plus Christmas Eve and New Year's Eve off
• Up to 5 days of special leave for important life events

About Us

Automated where it makes sense. Personal where it counts.

We are Lime Connect – an AI-first company and one of the top software scale-ups in Cologne. AI isn’t an add-on for us, it’s the core of what we build: our leading customer messaging solution for customer service, sales, and marketing combines AI agents, web chat, and mobile messaging, already automating the majority of all customer inquiries today. As part of Lime Technologies, our Swedish parent company, we combine international perspectives with the drive of a company actively shaping its next stage of growth. With us, you help shape things, not just execute them – with real ownership from day one, in a dynamic environment, and a culture that values results just as much as people. Weekly fika included.