Delta or Nabla: which AI to choose as a psychologist or psychiatrist?

We publish Delta. This page compares Delta with Nabla as honestly as we can, including the points where Nabla does better. Everything we say about Nabla comes from its public pages and from the press, consulted on 9 October 2026. When a piece of information is not published, we say so. If you spot a mistake, write to admin@mydelta.app and we will correct it.

Nabla in a few lines

A company born in Paris that is now mostly American

Nabla was co-founded by Alexandre Lebrun. It has offices in Paris and in Brooklyn (New York). Its product transcribes the consultation between clinician and patient, then drafts a medical note. There is also a dictation mode, a Chrome extension, a web app and iOS and Android apps.

In June 2025 Nabla announced a $70 million raise (Series C led by HV Capital), which brings its total funding to $120 million according to its press release. In the same release, the company says it is used by more than 85,000 clinicians and more than 130 healthcare organisations. These are the vendor's figures.

Who Nabla targets in October 2026

The short answer is large organisations, first of all in the United States. Here is what we found.

• Nabla's main website, in English, presents the tool as a clinical AI layer embedded in Epic and the other major medical record systems. The customers it names are American healthcare players such as Carle Health, Denver Health or CVS Health.
• The Series C press release talks about adoption across U.S. health systems. FrenchWeb places the 85,000 clinicians and 130 organisations “in the United States”.
• According to Maddyness (June 2025), Nabla had focused on the American market in recent years, and France accounted for “less than 5% of its business”.
• In July 2026 Nabla announced a new CEO, Brian Manning, who comes from healthcare technology sales. Alexandre Lebrun becomes Executive Chairman and Chief AI Officer. The announcement talks about large healthcare organisations and about bringing the tool to more clinicians across the country, meaning the United States.
• The posts on Nabla's blog in August and September 2026 are written for leaders of healthcare organisations.

Nabla has not left France, though. Its French website offers a “Try it free” button that opens an online sign-up, shows the logos of the French medical software Weda and Dr Santé, and lists several hospitals and clinics (Centre hospitalier d'Arles, Centre hospitalier d'Avignon, HFR Fribourg in Switzerland). Of the 38 testimonials on its French page, the large majority come from general practitioners. There is one psychiatrist and no psychologist.

For a mental health practitioner in private practice, the consequence is simple. Nabla can still be used, but it is not mainly being developed for this audience.

What Nabla offers for mental health

Nabla's French help centre lists seven report templates, including a “Psychiatry” template (with a mental health examination section) and a “Psychology” template (with a section on mental health history). The article does not say whether you can create your own template.

In the United States, Nabla highlights behavioural health. Its 2025 press release names this sector among those where adoption is growing, and a May 2026 post presents templates built with Catalight, a provider of services for children and families with developmental and behavioural health needs.

We found no Nabla page dedicated to psychologists, psychotherapists or a therapeutic approach (CBT, psychodynamic, systemic, EMDR).

How Delta works

Delta is an AI assistant for mental health professionals and allied health practitioners in France, Belgium and Switzerland. During the session, Delta transcribes what is said, then prepares a session report that you read and correct. You can also dictate your observations just after the session if you prefer not to capture anything during the appointment.

The report takes your specialty and your therapeutic approach into account. It is added to the patient record, so the whole follow-up and its progress are in one place. For example, in addiction care, you can see how a patient's substance use has changed over several months. Delta also drafts your assessment reports, letters and certificates.

Data is hosted in France with a host certified for health data (HDS). AI processing, transcription included, runs on servers located in France. The patient's name and identifying details are pseudonymised before they reach the AI, no audio file is kept, data is never used to train models, and it is encrypted in transit and at rest.

What Nabla does better than Delta

Nabla has several real strengths, and some of them matter a lot depending on your situation.

• Integration with medical software. Nabla integrates with Epic, Oracle Health and other hospital systems, and in France with Weda and Dr Santé. If you are a psychiatrist and your records already live in one of these systems, the note lands where you work. Delta keeps reports in its own patient record.
• Roll-out across an organisation. Nabla can equip a whole hospital, with API integration and data retention settings adapted to the organisation. If your hospital or clinic is choosing one tool for all its doctors, Nabla is built for that.
• All medical specialties. Nabla's testimonials come from GPs, cardiologists, neurologists, gynaecologists and other specialists, and Maddyness mentions 55 specialties covered. A psychiatrist who also practises general medicine, or a multidisciplinary practice, needs only one tool.
• Size and published audits. Nabla claims 85,000 users and publishes a SOC 2 Type II report and an ISO/IEC 27001 certification in its Trust Center. Hospital IT departments ask for these.
• Apps. Nabla offers a Chrome extension and iOS and Android apps, which are handy for a doctor who works in several places.

How they differ, point by point

Who they are built for

Nabla is built for doctors and healthcare organisations, with a stated priority on American health systems. Delta is built for mental health and allied health practitioners in private practice or small practices, in France, Belgium and Switzerland.

Following the patient from one session to the next

This is the most concrete difference. Nabla produces one note per consultation. For the tool to take the patient's history into account, its help centre suggests typing or dictating a “patient context” before you start (age, history, treatment, summary of the previous consultation). The help centre also says Nabla does not store patient data, and its Trust Center states that reports are kept for 14 days. Nabla is therefore designed to feed record software you already have, not to replace it.

Delta keeps every report in the patient record. Before a session, you find the thread of the follow-up without copying anything. In psychotherapy, where follow-up often lasts months, this matters.

Specialty and therapeutic approach

Nabla adapts the note to the medical specialty, with “Psychiatry” and “Psychology” templates. Delta takes your specialty and also your therapeutic approach into account. The record brings out the progress that matters in that approach over the sessions. A CBT psychologist and a psychoanalyst do not take the same notes, and Delta's report follows that difference. To see what a note looks like for each approach, see our clinical document templates.

Documents

Nabla can generate a letter from a consultation, as well as instructions for the patient. Delta drafts session reports, assessment reports, letters and certificates. For psychiatrists, our psychiatric consultation report template shows what this kind of document should contain.

Hosting and data security

Nabla's French page lists health data hosting (HDS, the French certification for hosting health data) among its compliance commitments, alongside GDPR. Its Trust Center does not mention an HDS certification. It lists HIPAA, GDPR, SOC 2 Type II and ISO/IEC 27001. It states that data for clients outside the United States is stored with Google Cloud, in European data centres located in Belgium, and that audio is not kept by default.

With Delta, data is hosted in France with an HDS-certified host, and AI processing also takes place in France. If hosting in France matters to you, the difference is clear. If you are unsure, ask each vendor for its HDS certificate and the name of its host. Our guide to HDS hosting explains what this certificate covers.

Price

Nabla publishes no prices on its French website. To find out the price, you have to sign up or contact the team. Third-party sites quote amounts, but we could not check them with Nabla. Delta publishes its prices. The free plan covers up to 10 sessions a month. The Pro plan costs €35 a month including VAT with no commitment, or €29 a month including VAT with an annual commitment (€348 a year). The 14-day trial does not require a bank card.

Summary

• Main audience
  • Nabla. Doctors and organisations, with priority on American health systems
  • Delta. Mental health and allied health practitioners in private practice
• Mental health
  • Nabla. “Psychiatry” and “Psychology” templates
  • Delta. Specialty and therapeutic approach taken into account
• Patient follow-up
  • Nabla. One note per consultation, context typed in by hand
  • Delta. Report added to the record, progress visible
• Integrations
  • Nabla. Epic, Oracle Health, Weda, Dr Santé, API
  • Delta. Delta's own patient record
• Hosting
  • Nabla. Google Cloud in Belgium for clients outside the United States
  • Delta. In France, HDS-certified host, AI in France
• Price
  • Nabla. Not published
  • Delta. Free up to 10 sessions a month, Pro at €29 or €35 including VAT

In Belgium and Switzerland

Nabla's Trust Center states that data for clients outside the United States is stored in Belgium, and its French website shows the logo of the Fribourg hospital HFR Fribourg. Delta is available to Belgian and Swiss practitioners. The rules on patient consent there differ from France. We cover them in our guide to patient consent for AI note-taking.

Five questions to ask Nabla before you decide

If Nabla interests you, these questions will get you a clear answer in a single exchange.

1. Where is the data from my account hosted, and can you send me your HDS certificate?
2. How much does a subscription cost for a solo private practitioner, and is there a commitment?
3. Can the “Psychology” or “Psychiatry” template follow my therapeutic approach?
4. How long do my reports stay in Nabla, and where should I keep them afterwards?
5. Can my patients' data be used to improve your models, and how do I opt out?

Which tool to choose for your situation

• You are a psychiatrist in a hospital or clinic. Start by checking what your organisation has already chosen. If it is Nabla, it will be integrated with your electronic record and it is the simplest choice.
• You are a psychiatrist in private practice and your records are in Weda or Dr Santé. Nabla saves you from copying your notes across. Check the price and the hosting before you commit.
• You are a psychologist, psychotherapist or psychiatrist in private practice and you follow your patients over months. Delta will suit you better. It keeps the thread of the follow-up in the record, takes your approach into account, hosts data in France and publishes its prices.
• You work in a private practice in Belgium or Switzerland. Both tools can be used. Delta was designed for private mental health practice, Nabla for doctors and healthcare organisations.
• You are still unsure. Try both on a few real sessions, with your patients' agreement, and compare the reports. Our article on patient consent for AI note-taking helps you inform them.

To compare with other tools, also read Delta vs Heidi, Delta vs Markus Santé and our comparison of AI note-taking software for psychologists.

Frequently asked questions

Sources

• Nabla, homepage (English)
• Nabla, homepage (French)
• Nabla, testimonials (French)
• Nabla, Trust Center (certifications, subprocessors, data location)
• Nabla, help centre, « Choisir un modèle de compte rendu »
• Nabla, help centre, « Contexte patient »
• Nabla, help centre, « Données patients »
• Nabla, Series C press release (17 June 2025)
• Nabla, Meet Brian Manning, CEO of Nabla (22 July 2026)
• Nabla, Catalight expands access and equity in behavioral health with Nabla (28 May 2026)
• Maddyness, « Nabla lève 70 millions de dollars » (17 June 2025)
• FrenchWeb, « Nabla lève 65 millions d'euros » (17 June 2025)
• Delta, pricing