How we work
理念Open source first
Our core tools are genuinely free and genuinely useful, with all code on GitHub. Don't judge an AI tool by its marketing screenshots. Open its output and click around.
Products over promises
Less narrative, more shipping. We use every product ourselves until it feels right, and every example we show is a real, downloadable, verifiable artifact.
Built in public
Progress, reasoning and dead ends are shared as we go, in English on X and in Chinese across our local channels. If the work is good, showing it costs nothing.
Zeng（增） means to add. He（和） means the sum. Read together: Addsum, the opposite of zero-sum. Most software quietly shifts value from one group to another and calls it a business. We want to build software that creates new value, where more people end up better off than before. AI now lets a tiny team build what used to take a whole company, which means one person can create leverage for thousands of others. The biggest opportunities won't come from replacing people. They'll come from unlocking people. That is the game worth playing.
Products
产品slide-maker
Papers, code and docs in. A deck you can actually present, out.
Addsum's open-source AI slide generator. Chat for a few turns inside Codex or Claude Code; it reads your material first, then hands back a real PowerPoint file: not images pasted on slides, not a web page pretending to be a deck. Every text box, shape and chart opens for editing.
- Real text boxes, real shapes, native charts. Click anything, edit it
- Speaker notes written into every slide, bullets reveal natively on click
- Eight template decks in English and eight in Chinese, all with real content
- MIT licensed. Download a finished deck first, then decide
Explainer Video
讲解视频From a document to a narrated explainer video, sharing DNA with slide-maker, and open source like it. Watch GitHub for the release.
Free and open source at launch
Simul Interpreter
增和同传AI real-time simultaneous interpretation. We are tuning the model and the cost curve, aiming for low latency at a price anyone can afford. Pay and start at launch, no human interpreter to book.
Billed per minute, pay for what you use
Open source, built in public
开源A good tool should be used freely before it is trusted. We give our best work away and let compounding do the rest.
Open source is not a marketing line for us. It is how we earn users and how we stay honest: the code is public, so anything we claim can be checked.
In English we build in public on X. In Chinese we publish on WeChat, Xiaohongshu and Douyin. Both audiences watch the same thing happen: tools being polished until they are genuinely useful.
Team
团队
Martin Lau
Co-founder · Head of Product
MSc in Electrical and Electronics Engineering, EPFL. Previously at a top-tier investment bank and a private equity fund.
Leo Lyu
Co-founder · Head of Engineering
PhD candidate in Medicine at Leiden University.
Two people, plus AI. Staying small, moving fast.