Independent comparison 2026
AI documentation tools, compared
What distinguishes Nixi from Doctolib, Tandem, and international vendors. A sober comparison with sources.
The differences between AI documentation tools live below the surface: in peer-reviewed clinical evidence, data residency, retention, and specialty depth. Nixi is the only tool with a peer-reviewed clinical study in a German specialty (EULAR Rheumatology Open 2025) and with zero audio/transcript storage in Frankfurt.
Comparison table
Superscript digits link to public sources (footer). Competitor claims are cited against their own publications.
| Tool | Peer-reviewed evidence (German specialty) | German medical ASR | Multi-speaker diarisation | Multilingual consultation in one session | German billing codes (GOÄ / EBM) | Data residency | Audio retention | Transcript retention | Model training on patient data | On-premise / federated (hospitals) | § 203 StGB-compliant contracts |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Nixi | EULAR Rheumatology Open, December 2025 ¹ | <5% WER | Built for complex histories | Doctor + patient in different languages | Native code suggestions | Frankfurt only | Never stored ³ | Zero retention | No | Yes, in preparation with university hospitals | Explicit, per customer |
| Doctolib AI | Internal study ² | EU-hosted, no specialty-trained ASR | Standard | One language per session | AI billing assistant | HDS-certified EU | Not stored | 48 hours ⁴ | Yes (opt-in/opt-out) ⁵ | No | Standard DPA |
| Tandem Health | Capio report (not peer-reviewed) | English-first, German added later | Standard | One language per session | SNOMED / ICD-10, no native EBM | EU | Not stored | Configurable | No | No | Standard DPA |
| Heidi / Abridge / Suki | None for Germany | English first | Standard | One language per session | Not supported | USA / global | Variable | 30 days (DAX) | Variable | No | Often unavailable |
Where the vendors substantively diverge
Three differences that matter day-to-day
1. Privacy that crosses other vendors' business-model boundaries
★Zero audio and transcript retention. § 203 StGB per practice.
Strengths
- Audio is processed in short segments and discarded immediately
- Transcripts are not stored beyond the session
- DPA closed explicitly per practice or hospital
- Frankfurt processing, no US transfer
Limitations
- Doctolib retains transcripts for 48 hours ⁴ and uses pseudonymised patient data for AI training (opt-out available) ⁵
- Microsoft Dragon Copilot retains audio + transcript for 30 days by default
- Tandem and Nabla don't store audio but keep transcripts in the cloud
- Price
- From €49/month
- Best for
- Practices with strict data-protection requirements (KV, supervisory authority, hospital network)
2. Peer-reviewed clinical evidence in a German specialty
EULAR Rheumatology Open, December 2025. 88 consultations. 0 serious errors.
Strengths
- Consultation time reduced in 82% of cases (72 of 88)
- 0 serious errors; all reported errors classified as minor
- 100% patient participation rate, no refusals
- 70% of patients rated the AI assistance positive or very positive
Limitations
- Voize has a comparable study, but only for nursing care (Charité, October 2025)
- Doctolib cites an internal study from its own organisation ²
- Tandem relies on the Capio report from Scandinavia, not peer-reviewed
- Price
- Study open access. DOI 10.1016/j.ero.2025.12.002
- Best for
- Practices that need durable evidence before rollout
3. Specialist-built, not a generalist tool
DAS28, UPDRS, pathology macros, GOÄ + EBM as standard.
Strengths
- Built by pharmacists with clinical experience
- Two specialist scientific advisors (PD Dr. Peer Aries / Rheumatology, Dr. Tiedge / Neurology)
- German billing codes (GOÄ, EBM) as standard feature
- Specialty-specific templates, not one-size-fits-all
Limitations
- Generalist tools (Doctolib, Heidi, jameda Noa) are cheaper if you don't need specialty-specific templates
- For general practice, paediatrics, or gynaecology without specialty-specific code logic, a generalist tool is sufficient
- Price
- From €49/month
- Best for
- Specialist practices in rheumatology, neurology, pathology, and adjacent fields
Frequently asked questions
What to know before switching
- Which AI documentation tool has peer-reviewed evidence in a German specialty?
- Nixi. The Knitza & Aries study was published in EULAR Rheumatology Open in December 2025 (DOI 10.1016/j.ero.2025.12.002). Setting: German rheumatology clinic, 88 consultations, 108 patients. Voize has a comparable study but for nursing care (Charité). Doctolib cites an internal study from its own organisation.
- Who stores transcripts and audio, and for how long?
- Nixi: neither audio nor transcripts beyond the session. Doctolib: transcripts for 48 hours (source: Doctolib Help Center article 40589528427156). Microsoft Dragon Copilot: 30 days by default for audio + transcript. Tandem and Nabla don't store audio but keep transcripts in the cloud.
- Which vendors train AI models on patient data?
- Doctolib uses pseudonymised patient data for AI training by default (opt-out available per practice; source: Doctolib privacy policy, February 2025). Nixi doesn't use audio. De-identified data may be used to improve the model under the DPA; full mechanism in the Privacy Policy §5.
- Which vendors offer § 203 StGB-compliant contracts?
- § 203 StGB compliance requires an explicit data-secrecy obligation on the processor. Nixi includes this clause explicitly per customer in every contract. Doctolib and Tandem use standard DPAs without § 203-specific language. International vendors (Heidi, Abridge, Suki) often don't offer § 203-compliant contracting at all.
- Which vendors support German billing (GOÄ / EBM)?
- Nixi: native code suggestions for GOÄ and EBM as a standard feature. Doctolib: AI billing assistant in the all-in-one bundle. Tandem: SNOMED- and ICD-10-based, no native EBM. Heidi / Abridge / Suki: no German billing logic.
- Which vendors operate exclusively in the EU?
- Nixi: Frankfurt only. Doctolib: HDS-certified in the EU. Tandem: EU. International vendors (Heidi, Abridge, Suki): USA or global, with data flows outside the EU.
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