Practice the
conversations
that matter.
Before they happen. Cortavia is the product studio behind KallosSim, VitalsVoice, and Reheara. All three use the Praxis AI engine for conversation practice and learning.
Three applications. One shared engine.
Cortavia brings together KallosSim, VitalsVoice, and Reheara — three focused applications for conversation practice, connected by the Praxis dialogue engine.
Praxis provides common conversation mechanics. Each application brings its own scenarios, learning context, and experience. AI feedback supports reflection; people retain professional judgement.
3
1
2026
The Cortavia index
Three focused applications, connected by the Praxis dialogue engine.
Bespoke where it matters, generic where it should be
We build for professionals, interviewers, and teams who want to prepare for important conversations. A shared dialogue engine supports distinct scenarios and learning contexts.
Professional & public-service teams
KallosSim supports conversation practice for people working through complex professional situations.
Interviewers & learners
VitalsVoice focuses on interviewing and communication skills through practice and reflection.
Organisations & learning teams
Reheara provides a setting for conversation rehearsal around team learning goals.
Education & training partners
Talk to us about scenarios, learning criteria, and how conversation practice could fit your training programme.
Principles behind every product
Practice with purpose
Start with the conversation and the skills someone needs to develop. Scenarios and feedback should serve that learning goal.
Feedback that invites reflection
AI-generated feedback supports learning and discussion. Professional judgement and decisions remain with people.
One engine, distinct applications
Praxis provides shared dialogue mechanics. KallosSim, VitalsVoice, and Reheara each own their learning context, content, user experience, and application systems.
Clear claims, clear evidence
We distinguish product design from demonstrated outcomes. Research partnerships, effectiveness claims, and professional endorsements need their own evidence.
Ethics, privacy & responsible AI
KallosSim, VitalsVoice, and Reheara use the Praxis AI engine. Our approach starts with fictional practice, human judgement, transparency, and respect for personal data. KallosSim's published policies provide the detailed reference; each application needs its own controls and privacy information.
Ethics, fairness & wellbeing
Practice should help people prepare for difficult conversations without putting real service users at risk.
Read KallosSim's ethics statement →Privacy & data rights
People should understand what is processed, why it is needed, who can access it, and how to exercise their rights.
Read KallosSim's privacy notice →AI transparency & human judgement
Be clear about what AI generates, what humans design, and where the system can be wrong.
Read KallosSim's AI transparency statement →EU AI Act & organisational governance
Intended use, human oversight, AI literacy, and evidence matter more than a blanket compliance badge.
Read KallosSim's organisational guidance →Build a practice experience around your team.
Tell us about the conversations your people need to prepare for. We can explore scenarios, learning goals, and how KallosSim, VitalsVoice, Reheara, or the Praxis engine could support your project.
Conversation-practice experiences
We build focused learning experiences around realistic dialogue, rehearsal, and reflection.
Scenarios and learning criteria
We work with domain specialists to shape scenarios and feedback around the needs of a training context.
Product and platform engineering
We connect shared engine mechanics to application-specific interfaces, identity, and data systems.
Evaluation and iteration
We define what needs to be tested, gather feedback, and improve the experience against agreed learning goals.
Frequently asked
What is Cortavia?
Cortavia is the product studio behind KallosSim, VitalsVoice, Reheara, and the Praxis dialogue engine. Our focus is conversation practice and learning.
What products does Cortavia build?
Our portfolio consists of three applications — KallosSim, VitalsVoice, and Reheara — and their shared dialogue engine, Praxis.
What is Praxis?
Praxis is the shared dialogue engine behind the three applications. It provides common conversation mechanics; each application has its own content, experience, and supporting systems.
Does AI feedback replace professional judgement?
No. Feedback is intended to support practice and reflection. It does not replace professional judgement or establish a learner's professional competence.
Can we discuss a training project?
Yes. Contact us to discuss your audience, scenarios, learning objectives, and the kind of practice experience your team needs.
How do I access the applications?
Visit KallosSim through its product link. For a VitalsVoice or Reheara demonstration, or a conversation about Praxis, email hello@cortavia.com.