DOCNUS vs ChatGPT: which one fits your document work?

As of 14 October 2026.

If you are looking for "ChatGPT for documents", you probably want to upload files and ask questions about them. ChatGPT can do that, and so can DOCNUS, but they are built for different jobs. ChatGPT is a general-purpose assistant that also reads files. DOCNUS is a shared document library for a team, where every answer cites a page and the same library feeds a privacy assessment, a knowledge graph and a list of contract obligations. This page sets out the differences as fairly as we can. Every fact about ChatGPT links to an OpenAI page, and every fact about DOCNUS describes what the product does today.

At a glance

Where ChatGPT is stronger

ChatGPT does far more than read documents. It drafts, rewrites, analyses data, searches the web and handles a much wider range of file types than DOCNUS, with a much higher per-file size limit (File uploads FAQ). If your question is "help me write a reply to this letter" rather than "where in our files does it say this", ChatGPT is the more natural tool.

It is also cheaper for individuals and very small teams. Plus is $20 a month, and Business for two people is $50 a month billed monthly or $40 billed annually (OpenAI pricing). DOCNUS Professional is $149 a month whatever the team size up to 15 users, so for one or two people ChatGPT usually costs less.

If you need your data stored in a particular region, OpenAI offers data residency at rest, including UK and European regions, for eligible Enterprise, Edu and API customers (OpenAI). DOCNUS does not offer data residency, and some of its subprocessors process data in the US.

Where DOCNUS is different

DOCNUS is narrower on purpose. It is built around one shared library per organisation, and everything it does comes from that library.

• Page-level citations on every answer. Search combines meaning-based and keyword search, then reranks the results, and searches again if the first pass is weak. Each answer points to the file and page so you can check it. See AI document search.
• A privacy assessment per document. On Professional and Enterprise, DOCNUS detects 50 categories of personal data and gives a verdict under EU GDPR, UK GDPR, CCPA/CPRA, a US state baseline, LGPD, PIPL and DPDP. The AI finds the facts and versioned rules in code decide the verdict, as described in AI finds facts, code decides. Values are stored masked. It is an automated risk assessment, not legal advice, and you should review the results.
• A knowledge graph and obligations. People, organisations, agreements and other entities are pulled from the same documents, with a profile page listing the documents that mention each one. Invoice due dates are collected on every plan, and renewals and notice periods on Professional and above, into a list you can export as CSV.
• Flat team pricing. Professional covers 15 users for $149 a month. For a team of 15, ChatGPT Business would be $375 a month billed monthly or $300 billed annually (OpenAI pricing), though that buys a much broader assistant.

DOCNUS's honest limits

• Only PDF, Word and plain-text files.
• Document and search caps on every plan, for example 500 documents and 1,000 searches a month on Professional.
• No Microsoft 365 or Google Drive integration. You upload files directly.
• No SSO or SAML. Google and Microsoft sign-in are available, but not single sign-on for your own identity provider.
• Data is processed in the US by subprocessors. We make no UK or EU residency claim.
• No certifications such as SOC 2 or ISO 27001.
• It is a young product.

When to choose which

Choose ChatGPT if:

• you want one assistant for writing, analysis, web search and the occasional file;
• you work with file types DOCNUS does not read, or very large files;
• you are one or two people and price per seat matters most;
• you need data stored at rest in a UK or European region and qualify for Enterprise or Edu.

Choose DOCNUS if:

• your work is answering questions from a fixed body of documents, such as contracts, policies or case files, and you need to show the page an answer came from;
• you want to know which documents hold personal data, of what kind, and how that maps to specific articles, for example when preparing a subject access request;
• you want contract obligations and the people and organisations in your files pulled out automatically;
• you are a team of several people and prefer one flat price.

Law firms should also read the SRA's guidance on AI tools and client confidentiality, which we summarise on our law firms page, before putting client documents into any AI product, including ours.

Using both

The two tools do not compete for every task, and many teams will use both. A sensible split is ChatGPT for drafting and general questions, and DOCNUS for the document library you need to search, check and assess. DOCNUS itself uses Anthropic Claude models for answers and OpenAI for embeddings, so if your organisation has a policy on AI providers, check both products against it. Our security page and privacy policy set out exactly which subprocessors we use and where.

You can try DOCNUS on the Free plan, with 5 documents and 30 searches a month, before deciding.