Chart
Hours of sun a day in Lisbon
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Every answer, pieced together.
Quick questions get a straight answer in seconds. Bigger ones are researched, written and checked in parts, then set into one clear answer while you read.
Free for Windows 10 and 11, with any AI model.
Mosaik is a Windows app. Send yourself the link and get it on your PC.
Windows only for now. Linux is next.
Dynamic output
The short answer first. Then the whole picture.
Most chat apps make you wait for one long reply. Mosaik answers a big question in two steps, so you can start reading straight away.
A straight answer in seconds.
Two to four sentences with only what's certain, so you're never staring at a blank page.
Then every part at once.
An outline appears, and each part gets its own AI to search, read and write. A big question can have eight of them working together.
Checked before you see it.
A part shows up only once it passes a check, and nothing you've already read is ever rewritten.
Small talk and quick facts still get one quick reply.
Should we switch our 1970s house in Minneapolis from a gas furnace to a heat pump?
Yes, if you choose a cold-climate model and seal the attic first. The best ones keep heating well below zero, and with Minnesota's rebates a winter costs about what gas does. neep.org
Switching a 1970s house to a heat pump
How they cope with a Minnesota winter
A cold-climate model keeps heating at −13 °F, and the best give 80 to 100% of their output at 5 °F. Below that, a backup coil or the old furnace takes over. neep.org
What a winter costs
Getting the house ready
Bottom line: get two quotes for a cold-climate model sized from a heat-loss calculation, and seal the attic before anyone measures.
Smart elements
Charts, checklists and calculators, inside the answer.
When numbers read better as a chart, Mosaik draws one. A plan comes as a checklist you can tick, a loan question as a calculator you can change, and a choice as buttons that ask the next question for you. It picks what suits each answer, and plain text when that's clearest.
Checklist
Before the move
Calculator
Car loan
Choices
Where are you flying from?
Your pick goes back as your next message.
Tabs and document layouts too, ready to save as PDF or Word. Anything that can't be drawn stays a plain table or list.
Smart mode
Two sliders. Mosaik tunes the rest.
Set how much an answer may cost and whether you'd rather have it fast or thorough. For each message, Mosaik then picks the model, how long it thinks, whether it searches, how many AIs work on it and how the answer is laid out. A model that's known to be bad at a job never gets that job.
Free models are the default. If you'd rather choose everything yourself, Manual mode puts each of those settings in your hands.
What Smart picked
“What's 15% of 80?”
Quick modelNo search1 AI
“Compare four heat pumps for a cold winter”
Stronger modelWeb search4 AIsA chart
And everything else you'd expect.
The everyday parts of a chat app, done with care. Click a picture to see the whole window.
Any model
Sign in to OpenRouter for hundreds of models, free ones included, or paste a key you already have.
Any file in
PDFs, spreadsheets, photos and recordings, sent in a form each model can take.
Data analysis
Questions about a spreadsheet are worked out with real Python, charts included.
Memory you can read
It remembers what you tell it, shows you all of it, and forgets on request.
Voice
Talk instead of typing, in any language, and have answers read aloud.
Prompts
Save prompts with blanks to fill in, and run them by typing / in the message box.
An editor beside the chat
Long drafts and code open next to the conversation, with every change shown.
Versions
Try again as often as you like. Every version of an answer is kept.
Find any chat
Search every chat by what was said with Ctrl K, and keep them in folders.
Import
Bring your chats over from ChatGPT and Claude.
Every step in view
Open any answer to see each search, page and tool it used.
Ask from anywhere
Press Alt Space in any app for a quick question.
Free, with nothing to sign up for.
Chat is the whole app, and it stays free. Paid models are billed by your provider at their own price, usually a cent or two an answer. Free models cost nothing at all.
No subscription
No fee, no trial and no account with us. Download it and start.
Your chats stay home
Chats and settings live on your PC, and your key sits in Windows Credential Manager. We have no server that holds them.
No surprise bills
Every answer shows its price, and a monthly cap is on from the start. Change it, or stick to free models.
No tracking
There are no analytics in the app or on this site. Beyond a daily count of downloads and update checks, we only know what you tell us.
Early days
Made by one person, in the open.
I'm building Mosaik on my own. I wanted one app that's quick with small questions, careful with big ones, and honest about how it got there. It's early, so you'll find the odd rough edge. When you do, tell me: the person reading your report is the one who fixes it.
The feedback button in the app, the community or [email protected] all reach me.
Mosaik in your browser
The same chat on any computer, with nothing to install.
Linux
Windows comes first. Linux is next, and macOS may follow.
Mosaik on your phone
A mobile app on the same idea: your key and your models.
Mosaics
Long projects, with tools for code, writing, art and research. An optional paid add-on. More
Hear about the big stuff.
New releases, Linux and the phone app, and Mosaics when it's ready. A few emails a year.
Questions
Is it really free?
Yes. Chat is free and stays free, with no subscription, trial, account or message limit. Paid models are billed by your provider at their own prices, and free models cost nothing. Paid add-ons like Mosaics will come later, and they'll be optional.
So how does Mosaik make money?
It doesn't yet, and it won't from you using Chat. Later it will from optional add-ons, never from ads or your data. For now the goal is a chat app good enough that you'd tell a friend about it.
What does "bring your own key" mean?
Mosaik doesn't resell AI. You connect OpenRouter, in one click or with a key you already have, for hundreds of models from OpenAI, Anthropic, Google, Meta, DeepSeek and more. Your key is kept in Windows Credential Manager. Mosaik isn't affiliated with OpenRouter.
Where do my chats go?
They stay on your computer. Your messages go to the model you picked, through the provider you connected, and web searches go to the search engines that answer them. We don't receive any of it.
Why does Windows warn me when I install it?
The installer isn't code-signed yet, so SmartScreen doesn't recognise it. Click More info, then Run anyway. The Download page lists the file's SHA-256 if you want to check it first.
Is there a Mac, Linux, phone or browser version?
Not yet. Mosaik in your browser is coming soon, Linux is next for the app, a phone app is planned, and macOS may follow. The roadmap has the rest.