SumizAI vs Deta Surf

What Deta Surf is

What Deta Surf is

Deta Surf is an app built by Deta, a startup with teams in Berlin and New York, that combines a web browser, a file manager, and an AI assistant inside a single window. Instead of separate tabs, folders, and a chat window for a language model, Surf organizes work around topic-based notebooks that collect everything tied to a given project or research topic.

Key features

You can drag a PDF into a notebook, paste a link, open a YouTube video, or jot down a quick note — everything lands in an indexed local library that stays available even offline. The built-in AI assistant has access to every open tab, file, and note at once, answering questions with precise references, including timestamps in video material and source highlights in documents. The app supports multiple large language models — including GPT-4o, Claude, and Gemini variants — chosen depending on the task at hand. A feature called Surflets lets you build custom, AI-generated desktop-style widgets, such as a calculator or a translator, right inside the workspace.

Who it's for

Deta Surf appeals to people doing deep research — researchers, students writing a thesis, investigative journalists — who juggle dozens of sources at once and need one place where everything gets collected and stays searchable. It also suits anyone tired of switching between a separate browser, a notebook, and an AI chat window for every research project.

Use cases

In practice, Surf works well for gathering material for a longer article or report — every article, PDF, or recording visited lands in one topic notebook, and the AI assistant can summarize all the collected sources at once. A student preparing a thesis can ask questions spanning a dozen open tabs at the same time without manually switching between them. Analyzing a long YouTube recording with automatic references to specific timestamps speeds up pulling out key conclusions without rewatching the whole thing.

Pricing and business model

The app is free and open source, still under active development in beta since its fall 2025 launch. Deta's business model around Surf is still taking shape as the product matures — worth checking the project's current page before relying on specific licensing terms for commercial use.

Limitations and what to watch for

Beta status means features and the interface can shift between updates, and some parts can be unstable. The app is available on Mac, Windows, and Linux as desktop software — the lack of a native mobile version limits its use on the go compared to purely cloud-based research tools.

AI notes embedded with source context

Because Surf's AI assistant answers with references to specific parts of open documents and recordings, an ai notes entry created during a research session carries the context of its source along with it right away — a different approach from separately copying fragments of a conversation into an external notebook and manually noting where the information came from. Researchers building up a running set of ai notes across a project appreciate that the context doesn't vanish once a browser tab closes.

Local storage as the foundation for privacy

User data in Surf is stored locally on the device, setting it apart from purely cloud-based research tools that send every open document to the vendor's server. For people working with sensitive material — journalists protecting sources, for example — that's an architectural difference worth weighing when choosing a tool.

Competing with NotebookLM and similar tools

Deta Surf is often compared to Google NotebookLM for a similar idea — gathering sources in one place and asking questions across all of them at once — but it differs by combining that feature directly with a full web browser, instead of requiring you to manually upload every document to a separate web service.

The pace of development during beta

Since its October 2025 launch, Surf has received frequent feature updates, which for early adopters means both quick access to new capabilities and the risk that a feature description from a few months ago may no longer match the current version — worth checking the project's official page rather than relying on older reviews.

What's worth checking before choosing

Before relying on it for serious work, check the current stability of the beta release, availability on your own operating system, and whether the query limits on your chosen language model fit the intensity of the research work you're planning.

Bottom line

Deta Surf is an experimental combination of a browser, file manager, and AI assistant built around topic notebooks, still under active beta development. Anyone who wants ai notes from a research session to form automatically with source context, rather than requiring manual copying from a separate chat, should consider this tool.

Comparison with SumizAI

Deta Surf and SumizAI address different stages of working with information. Surf focuses on gathering and searching sources during research — browser, files, and AI in one window. SumizAI focuses on what happens after a conversation with a model — turning answers worth keeping into ai notes saved as Markdown files in a vault the user owns, with automatic duplicate checking and a place in the table of contents. SumizAI has no built-in model — the user connects their own key to one of seven providers, including a local Ollama option, paying that provider directly. Anyone doing broad research across many sources at once will appreciate Surf; anyone who wants conclusions from AI conversations to land automatically in a lasting, searchable notes archive will find SumizAI the better-fitting tool.

That is our reading of the record. For AlternativeTo's own wording, see its page for Deta Surf — the facts above were read on 2026-08-16.

What SumizAI is

A note-taking application built around a conversation with an AI model. You ask a question, the answer streams back, and the answers worth keeping become Markdown notes — filed into a vault that is a folder on your own disk.

A vault is a directory holding base.md, a generated table of contents up to six levels deep, and a notes/ folder with one .md file per note. Before a note is written it is checked against the ones already there, so the fourth note about the same idea gets merged instead of added. Links between notes are ordinary Markdown links to files that exist.

The model is never ours: you bring your own API key to one of seven providers — Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server — and pay that provider directly. A question sends the table of contents plus at most five relevant notes within a 24,000-character budget, and the app shows you which five it used.

Every answer kept this way becomes one of these ai notes, ready to search again months later without hunting back through old chats.

Side by side

Where they differ

• Both mention AI. The difference is whose key it runs on: SumizAI never resells inference — you connect one of seven providers (Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server) with your own API key and pay that provider directly. Check what Deta Surf does with the model bill before comparing prices.
• Deta Surf is open source (Apache-2.0), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for Deta Surf. The guarantee SumizAI offers instead is structural rather than legal: the notes are Markdown files in a folder you chose, so they open in any editor whether or not the application is running.
• AlternativeTo's description of Deta Surf does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard .md files to a folder you picked, and an unpaid account can still export all of them.
• AlternativeTo lists no mobile version of Deta Surf. SumizAI runs on macOS, Windows, iOS and Android.
• Both are run from the EU: SumizAI's operator is registered in Poland and the servers are in Germany.

Which one to pick