AI models

Any model. Every answer evidenced.

You decide which models are allowed – large models via API or open models on your own servers. c:node picks the right one for each question. The check at the source stays the same for every model.

Claude

Anthropic

Via API in the EU region

GPT

OpenAI

Via API

Gemini

Google

Via API in the EU region

Mistral

Mistral AI, France

Via API · EU provider

Qwen

Open model

On your servers · air-gapped too

Llama

Open model

On your servers · air-gapped too
c:node Research · AI models

Which AI model do you really need?

Reading time ~6 minBasis Stanford AI Index + 3 studies, verifiedTopic Freely available vs. boughtAs of 2025–2026
In short

You don't have to take the biggest or most expensive AI model. Two things have changed: First, the freely available (“open”) models are now almost as good as the expensive, paid ones from the big US providers. Second — and more important for a business: for your specific task, a small model trained on your data beats the big all-rounders. And the more of your own data, the better it gets. That's exactly what c:node builds on: it uses open models of your choice and adds a knowledge store on top that grows with every case in your organisation — instead of locking you into a single provider.

A quick note on the percentages below: “accuracy of 90 %” means: out of 100 cases, the model classifies about 90 correctly. A “gap of 1.7 %” means: the freely available model is only 1.7 percentage points behind the best paid one — practically level.

8.0% → 1.7%
That's how far the best freely available models trailed the best paid ones — almost caught up in just 13 months (Stanford AI Index 2025).
94.6% vs 84.9%
A small model trained for the task gets it right more often than one 10× larger — on the same specialist task.
37% → 75%
That's how much an open model improved on a specialist task after being trained on the right data.

1 Freely available models are almost as good as the expensive ones.

For a long time, top performance was only available from the big, paid US models. That's no longer true. The Stanford AI Index 2025 measures how far the best freely available models trail the best paid ones — based on which answer people prefer in a direct comparison. This gap has practically shrunk away within a year:12

Jan 20248.0%
Mid 20244.2%
Feb 20251.7%

Only on the hardest tasks (such as programming or PhD-level specialist knowledge) are the paid models still a few points ahead. For the vast majority of everyday tasks the difference is small today — and freely available top models such as Kimi K3 sit right behind the market leaders at a fraction of the price.7

2 For your task, a small model beats the big all-rounder.

The decisive point for a business: you don't need a model that can chat about everything — you need one that reliably solves your task. That's exactly what scientific studies show again and again: a small, freely available model trained specifically on your domain data (experts call this “fine-tuning”) is as good as the big all-rounders or better — at a fraction of the size and cost. In the table, the small specialist model is on the left, the big all-rounder on the right; the number is the hit rate:

The taskSmall specialist modelBig all-rounderSource
Explaining programming errorsQwen-4B — practically level with GPT-4.1GPT-4.1arXiv 2507.05305
Sorting topics correctlyLlama-2-7B — 86.4% correctChatGPT-4 — 83.4%arXiv 2411.00890
Assigning specialist categoriesLlama-2-7B — 94.6% correctLlama-2-70B (10× larger) — 84.9%arXiv 2411.00890
Classifying documents reliablyQwen-3.5-27B (local) — 95.0%Paid models — 75–80%arXiv 2605.20368

Briefly explained: “94.6% correct” means the model was right in about 95 out of 100 cases. In the table, the small, specialised model almost always wins — even though the all-rounder is much larger and more expensive. The reason is the targeted training on the respective task.

3 The more of your own data, the better.

Perhaps the most important finding: the model gets better the more of your own examples it receives. In one study, the hit rate of the same model rose from 84.8 % to 94.6 % — simply because it was given around 76,000 examples to learn from instead of 5,000.4 This is exactly where c:node comes in: c:node isn't a fixed, finished model, but a knowledge store that grows with every case in your organisation — the longer you work with it, the more precise and traceable the answers for your area become.

In short: It's not the biggest model that wins, but the one best tuned to your data. And you have data — it grows every day.

4 How c:node uses this: three layers.

c:node brings exactly these findings together in three layers — separated and sealed off for each customer:

1

Base model (pre-trained)

An open, pre-trained model provides language and general knowledge — interchangeable without changing the traceable logic. The foundation.

2

Fine-tuning on your domain

On top comes fine-tuning on your specialist tasks — exactly the step that brings small open models level with the big generalists (see §2 and §3).

3

Knowledge graph + ontology

Both ground every answer in your facts and firm rules — the neuro-symbolic part. That keeps the answer traceable – anything that can’t be evidenced is marked as open. The science behind it →

All three layers grow with every case, per tenant: more domain data sharpens the fine-tuning, every new piece of evidence extends the knowledge graph and ontology. The longer c:node works in your organisation, the more precise and traceable it becomes — isolated, on-prem if you wish, with data protection under the GDPR.

5 And it works EU-sovereign.

You don't depend on US providers for any of this. Germany's Aleph Alpha offers Pharia, a multilingual model (including German), and the complete stack including weights and runtime for on-premise operation — trained in line with EU and national law.5 c:node is model-agnostic: c:node runs on open models of your choice, interchangeable without changing the traceable logic — in the cloud, on your server or offline.

6 Why AI leaderboards should be read with caution.

A fair comparison needs caution: on many well-known tests, the top models today all score above 90 % — the rest is hardly a difference any more, but measurement noise. A “number 1” headline therefore says little, because the test method alone often shifts the result. We deliberately show no day-to-day snapshot here, but the evidenced trends — and link the ongoing public leaderboards for you to check yourself:

Sources

  1. Stanford HAI — AI Index Report 2025: open models closed the gap to closed ones from 8 % to 1.7 % in one year. hai.stanford.edu…
  2. Analysis of the open-vs-closed gap (Chatbot Arena): 8.0 % (Jan 2024) → 4.2 % (mid 2024) → 1.7 % (Feb 2025). hankernest.in…
  3. Fine-tuning small open models on a specialist task: Qwen-4B within ±0.10 of GPT-4.1; large gains in correctness/discrimination. arXiv:2507.05305, 2025. arxiv.org…
  4. Domain fine-tuning: Llama-2-7B reaches ChatGPT-4 level on social-science tasks; accuracy rises with data volume (5K→76K: 84.8 %→94.6 %). arXiv:2411.00890, 2024. arxiv.org…
  5. Aleph Alpha — Pharia-1-LLM (7 bn parameters, multilingual, on-prem with weights + runtime, trained in compliance with EU law). aleph-alpha.com…
  6. Local fine-tuning beats commercial models on specialist classification: Qwen-3.5-27B 95.0 % vs. 75–80 %. arXiv:2605.20368. arxiv.org…
  7. LLM-Stats — open top model (Kimi K3) right behind the proprietary market leaders, at a fraction of the price. llm-stats.com…

The figures come from the Stanford AI Index 2025 and peer-reviewed studies (as of 2024–2026). Day-to-day model rankings change quickly — for snapshots, please use the linked live leaderboards. c:node is model-agnostic; the models named are examples, not an exclusive commitment.

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