Lead Software Engineer - Applications

Kleio; Paris; On-site; EUR 90,000 - 130,000; Full time

Job summary

Kleio is building Persuasive AI to revolutionize customer engagement and lead conversion. We seek a Lead Software Engineer – Applications to design and develop AI-powered, user-facing applications for customers, partners, and internal teams.

As a hands-on leader, you will own projects end-to-end, integrate with CMS/CRM systems, and drive architecture, UI/UX, and deployment decisions in a fast-paced, collaborative environment.

Qualifications

• 3+ years of professional full-stack development experience.
• Proven track record of designing and building scalable web applications.
• Strong hands-on experience with frontend frameworks; Svelte experience is a plus.
• Ability to take full ownership of projects, from concept to deployment.
• Excellent communication skills in English, with the ability to present ideas to customers and product managers.

Responsibilities

• Design and develop user-facing applications that enhance AI interactions and system configurations.
• Build integrations with third-party platforms (e.g., CMS, CRM).
• Contribute to cross-team technical discussions on architecture, UI/UX, back-end development, and integrations.
• Engage directly with customers to demonstrate Kleio’s capabilities and provide technical support.
• Help grow a high-performing, diverse engineering team.

Skills

Full-stack development

Web applications

Frontend frameworks

English communication

Agile development

Education

Bachelor's degree in Computer Science or related field

Tools

Svelte

Job description

We are looking forward to receiving applications from top talents.

Kleio was recently founded to revolutionize how companies engage with customers and boost sales.We are building Persuasive AI: a multi-agent conversational AI capable of autonomously engaging consumers in rich conversations to capture and convert leads.We are seeing strong traction across industries such as travel, real estate, domestic appliances, and cosmetics. Now, we are looking for highly skilled software engineers who believe AI will redefine digital interactions.

The Role:

As a Lead Software Engineer – Applications, you will play a pivotal role in developing AI-powered user-facing applications for end users, customers, partners, and internal teams. You will design and build:

• Conversational interfaces – web-based AI chat experiences with dynamic interaction modes.
• Multichannel AI interactions – rich messaging experiences across WhatsApp, Messenger, SMS, and other platforms.
• AI cockpit dashboards – advanced tools for customers to review conversations, extract insights, manage leads, and configure AI behavior.

As an early team member, you will help shape our company culture, hire top talent, and build cutting-edge AI-driven applications.This role is ideal for someone who thrives in a fast-paced, collaborative environment and is capable of executing precisely.

Responsibilities :

• Design and develop user-facing applications that enhance AI interactions and system configurations.
• Build integrations with third-party platforms (e.g., CMS, CRM).
• Contribute to cross-team technical discussions on architecture, UI/UX, back-end development, and integrations.
• Engage directly with customers to demonstrate Kleio’s capabilities and provide technical support.
• Help grow a high-performing, diverse engineering team.

Our stack:

We prioritize proven, modern technologies that allow us to move fast and efficiently. Our current stack includes:

• AI Infrastructure: Hosted LLM services (open & closed source LLMs)
• Databases: GCS, Redis, relational, vector, and graph databases

Qualifications :

• 3+ years of professional full-stack development experience.
• Proven track record of designing and building scalable web applications.
• Strong hands-on experience with front-end frameworks; Svelte experience is a plus.
• Ability to take full ownership of projects, from concept to deployment.
• Excellent communication skills in English, with the ability to present ideas to customers and product managers.

Preferred Qualifications :

• Interest in Generative AI and experience integrating LLM APIs.
• Degree in Computer Science, Mathematics, or a related field.
• Familiarity with Agile development methodologies.
• Experience leading engineering teams or projects.

Build Agentic Commerce with Kleio

Join the team building the Knowledge Engine and the orchestrated AI agents behind complex, high-value enterprise sales.