Delta vs Heidi: which AI assistant for psychologists?

We make Delta. This page compares Delta with Heidi as honestly as we can, including where Heidi does better. Information about Heidi comes from its website, checked on 8 October 2026. When something is not published, we say so.

In short

• Heidi is a very complete international tool for every health profession, with a free version.
• Delta is built for long-term follow-up in mental health and allied health, with a patient record that updates after every session.

Heidi in a few lines

Heidi is an Australian company expanding in Europe, reporting close to 100 million dollars raised in total. It serves every health profession, from doctors to psychologists. Heidi transcribes the consultation and writes a note following the chosen template, as well as letters. A library of user-made templates exists for psychologists. Heidi says it deletes audio after transcription, removes identifying details before processing the session and does not use data to train its AI. Its security page shows ISO 27001 and SOC 2 among others.

Delta in a few lines

Delta is an AI assistant for mental health and allied health professionals in France, Belgium and Switzerland. During the session, Delta transcribes what is said. Or after the session, you dictate your observations. Delta then writes the session report and adds it to the patient's record. The record updates itself with a summary of the follow-up, the goals being tracked and the topics for the next session.

Data is stored with a host certified for health data (HDS). The patient's name and anything that could identify them are pseudonymised before reaching the AI. No audio file is kept, and data is never used to train models. Delta costs €29 per month incl. VAT with a yearly plan, or €35 without commitment, after a 14-day trial with no credit card.

What sets them apart

Patient follow-up

Heidi produces one note per consultation, which you can enrich with context. Delta keeps a record that updates itself after every session, with a summary of the follow-up, the goals being tracked and the topics for the next session.

Specialisation

Heidi covers every specialty, and its featured templates often follow English-speaking formats. Delta is built for mental health and allied health, and takes your therapeutic approach into account.

Documents

Both write letters from the session. Delta also writes certificates and assessment reports.

Data hosting

We could not find on Heidi's public pages where French practitioners' data is hosted, nor any mention of HDS certification, which French law requires from a health data host. Delta uses an HDS-certified host.

Price

Heidi has a free version and paid plans whose prices are not shown on its French pricing page. Delta shows €29 per month incl. VAT with a yearly plan, €35 without commitment, and a free version limited to 10 sessions per month.

Which one to choose?

Heidi suits you if you want a very complete tool used in many countries, with a free version, as long as you get a clear answer on where your data is hosted.

Delta suits you if you follow patients over months and want a record that keeps track of the follow-up, with HDS-certified hosting.

Further reading

We also compare Heidi, Markus Santé, Pllume, myCR, PsyNote and ChatGPT in our comparison of AI note-taking software for psychologists.

Sources

Checked on 8 October 2026: Heidi, security, Heidi, pricing.

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