Showcasing what cross-functional teams built at pafin Hackathon through AI-driven development

pafin Inc., the company behind cryptact, a crypto tax platform with more than 200,000 users in Japan, today launched a dedicated page on its website for its internal hackathon, pafin Hackathon. Two projects from pafin Hackathon 2026 have already launched: fakestream, an open-source emulator for developers, and Sumazou, a service that sends medical scan images straight to patients' smartphones and went on sale on Oct. 1.

pafin first held the hackathon in 2024. The second edition, pafin Hackathon 2026, took place in June with the goal of putting AI tools to work across the whole company. Teams had just a few days to take an idea from plan to working prototype. The page introduces each edition of the hackathon, the teams behind it and the projects they built.

What sets pafin Hackathon apart

Mixed teams, open briefs

Each team mixed engineers with colleagues from business development, marketing, customer success, HR and design. Each team picked its own project, with no requirement to tie it to pafin's existing products.

24 participants, 11 nationalities

The participants are from Japan, Morocco, France, Belgium, India, Nepal, China, South Korea, New Zealand, Canada and the United States.

Beyond the prototype

In addition to the projects released publicly, some hackathon projects are now part of how pafin works every day. Two internal tools from the first edition in 2024 are still in use today: pafin TV, which shows daily sales and other figures on the office TV, and bottin, a directory that gathers pafin’s internal tools in one place.

Why pafin runs a hackathon

“AI is changing the way we work, and we have to keep up,” said Amin Azmoudeh, Co-CEO of pafin. “We run this hackathon for three reasons. We want everyone at pafin to be fluent with AI tools. We want to close the gap in how different teams use AI. And we want to find the next products and businesses worth building.

“When people build something side by side with colleagues who know the tools well, it changes how they work every day. That sharpens our creativity and problem-solving, and it’s what keeps us building services our users actually find useful.”

Projects from pafin Hackathon

fakestream (2026 hackathon · open source)

fakestream is a small local emulator for Amazon Kinesis Data Streams, AWS's data streaming service, that runs on a developer's machine or in a CI job. Written in Rust, it was built to solve a problem in pafin's own development environment. pafin released it on Sept. 7, 2026, as open source under the MIT license, which allows commercial use and modification.

GitHub: https://github.com/pafin-inc/fakestream

Sumazou (2026 hackathon · on sale)

Sumazou works with diagnostic images, such as CT and MRI scans, that hospitals give patients on a CD or DVD. From a dedicated kiosk installed in the hospital, it sends those images directly to the patient's own smartphone. The patient inserts the disc into the kiosk and scans a QR code with the free Sumazou app, and the whole transfer happens right there in the hospital. pafin began selling the service on Oct. 1, 2026, and announced that Kanto Neurosurgical Hospital has adopted it.

Website (Japanese): https://sumazou.com/

Crypto Tax Simulator (2024 hackathon · free tool)

This free tool estimates how much tax users would owe on crypto gains under Japanese tax rules, based on their annual income and crypto profits. It also works for sole proprietors. Released on Dec. 2, 2024, it passed 70,000 users in July 2025.

Tool (Japanese): https://www.cryptact.com/crypto-tax-simulator

Other projects presented at the hackathon

• Cryptrack: a single feed for crypto regulation, exchange and coin news
• Emojact: a tool that finds custom Slack emoji by meaning
• necho: a social network where people hang out and do nothing in particular with AI companions that take the form of cats, rocks and clouds

About pafin Inc.

Services

cryptact: automated crypto tax calculation
With more than 200,000 users in Japan, cryptact is one of the country's largest crypto tax calculation platforms. It provides automated profit-and-loss calculation and portfolio management to help users prepare their tax returns.
Website: https://www.cryptact.com/en
X: https://x.com/CryptactGlobal

Guardian: crypto tax filing support
Crypto-savvy tax accountants and a dedicated calculation team handle everything from profit-and-loss calculation to filing the tax return.
Website: https://guardian.pafin.com/

defitact: a portfolio tracker for Web3
Enter a wallet address and defitact instantly pulls together your on-chain transactions and visualizes your portfolio. It shows activity across multiple decentralized applications, along with real-time balances and the market value of the assets in your wallet.
Website: https://www.defitact.com/

Company Profile

Company Name: pafin Inc.
Location: Frontier Kojimachi 5F, Kojimachi 3-2-4, Chiyoda City, Tokyo, Japan 102-0083
Representative Directors: Amin Azmoudeh, Co-CEO / Gaku Saito, Co-CEO
Date Founded: January 2018
Website: https://www.pafin.com/
YouTube: https://www.youtube.com/@pafin

Media Contact
pafin Inc. Public Relations
Email: pr@pafin.com