SumizAI vs FenxChat AI

What FenxChat AI is

What FenxChat AI is

FenxChat AI is a Dutch, privacy-first AI chat app for iPhone — one app, every model, zero data stored. The app dynamically picks the best model for every message, without storing any user data. Instead of manually deciding which model to use for a given question, FenxChat AI does it automatically, analyzing the nature of the query and routing it to whichever model best fits that task, sparing the user from having to track which provider offers the best value for money in a given week.

A freemium model lets people try core functionality for free, while a paid subscription unlocks full access to every supported model.

The "zero data stored" principle goes a step further than the typical privacy claims of most AI assistants, which often keep chat history on servers even under encryption guarantees. FenxChat AI eliminates that problem at the root by not storing data at all, meaning there's nothing to steal even if a provider's servers were ever breached — the only valuable knowledge left after a conversation is ai notes the user deliberately chose to save.

Someone using FenxChat AI, valuing exactly that no-data-stored approach, has to accept the lack of built-in chat history as a tradeoff — every chat session is ephemeral, disappearing once the app closes, with no way to return to it later. That's a deliberate compromise between privacy and convenience, typical of tools maximizing data security, but a painful one for someone who remembers a great answer a week later and can no longer find it anywhere.

Someone working on several projects at once on an iPhone, switching between FenxChat AI and other tools throughout the day, feels the lack of chat history especially acutely when returning to an earlier session after a break for a meeting or another task and can no longer reconstruct exactly how the earlier conversation with the assistant went.

SumizAI complements FenxChat AI exactly at that point: since the app itself deliberately stores nothing, valuable findings from a conversation have to be deliberately moved somewhere else before they disappear for good — as ai notes in a local Markdown file, fully controlled by the user, aligned with the same zero-trust philosophy toward external servers. Someone using FenxChat AI for important decisions ends up with a lasting record in the form of ai notes, even though the app itself retains nothing.

These tools complement each other: FenxChat AI guarantees maximum privacy by deliberately storing no data, while SumizAI gives the user a deliberate choice of which conversation findings to keep for longer as these notes, instead of losing everything unconditionally the moment the app closes. Someone who values privacy but doesn't want to lose valuable knowledge gets the best of both worlds this way: an ephemeral conversation leaving no trace on any server, and lasting these notes stored purely locally, on their own terms.

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

• FenxChat AI is a place to have the conversation. SumizAI is not a chatbot — the conversation is the input, not the product. What comes out of it is a .md file with a title, a place in base.md and a duplicate check against the notes already in the vault. If you only want to talk to a model, you do not need SumizAI.
• FenxChat AI is freemium: there is a free tier and a paid one, and the line between them is the thing to read before committing. SumizAI has one plan at a dollar a month, so there is no feature held back for a higher tier — and an unpaid account still opens and exports every vault it already has.
• AlternativeTo's description of FenxChat AI 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.
• Both are run from the EU: SumizAI's operator is registered in Poland and the servers are in Germany.

Which one to pick