Kommitly

Landing Page
Discovery Page
Wallet Page
Impact Page
Stats/Market Page
Account Page

Inspiration

Anyone who has bought or sold on Facebook Marketplace or Craigslist knows the feeling: you agree on a time, drive across town, and nobody shows up. Or the buyer says "is this still available?" then disappears, never to be heard from again. Flaking costs nothing, so people do it constantly, and strangers meeting in person have no reason to trust each other. We wanted to fix the incentive, not just the interface. What if both sides had a little skin in the game, and a broken promise did some good instead of just wasting someone's afternoon?

What it does

Kommitly is a local marketplace where buyers and sellers each put down a small, refundable commitment fee to prove they'll show up. It works in four steps:

Browse and search nearby listings. Sellers set where and when they're willing to meet.
The buyer requests a meetup and puts down their fee; the seller puts down theirs when they accept.
Both people check in by GPS at the agreed spot, and the buyer scans the seller's QR code to confirm they met. Both fees are refunded instantly.
If the buyer wants the item, a second QR code lets them pay the seller directly. You're committing to meet, not to buy.

How we built it

We built Kommitly with SvelteKit and TypeScript, strongly utilizing its server-side rendering and SEO capabilities, and Supabase for the database, authentication, file storage and server functions. Payments, stakes and refunds run on Solana (devnet), with wallets for every user and charity. We also used the open-source tool AG Charts to display our stats charts, to better visualize the data and make it digestible for users with a cool stock-looking chart. Lastly, we used Mapbox to map users' locations against the meetup spot, so we can verify whether they are eligible to check in.

Market Built on Decentralized Reputation: How it works

Kommitly uses a self-correcting reputation system. Each user starts from a neutral reputation of 1.000, which moves up or down based mainly on their commitments_successful, commitments_cancelled, and commitment_checkins. The platform then calculates the average_reputation across the marketplace and uses it to adjust the base_commitment_fee: if the market reputation drops below 1.000, the base fee increases slightly; if it rises above 1.000, the base fee decreases. A user’s own reputation can then further adjust the amount they personally need to commit. In the Wallet/Account page, users can see their reputation score, commitment stats, the current market reputation, and how that market score is affecting the base commitment fee.

Challenges we ran into

One of our biggest challenges was clearly defining the problem behind our marketplace idea and making sure it was one worth solving. The next challenge was coming up with a formula for computing market reputation and individual reputation, and correlating that with the base fee to ensure a self-correcting market built on decentralized proof of trust.

Accomplishments that we're proud of

Connecting Solana with the app was a challenge, as it was something we hadn't used before. We are also very proud to have taken the time to really optimize the idea and define a clear action plan, which we successfully executed within the allotted 24 hours.

What we learned

We learned that incentives change behaviour more than rules do. A small refundable fee makes people far more likely to follow through than any "please don't flake" message. We also learned how much care goes into handling money in software, how to work with Solana wallets and transactions, and how important it is to scope tightly when time is short.

What's next for Kommitly

Add a function to lower the cost in case you bargained for a lower price during the meetup, and add functionality to report users, open disputes, and review sellers. Next, move the Solana wallets from devnet to mainnet so real money can be used to make payments.

TEST USERS

Test User 1:
Email: [email protected]
Password: hello123
Test User 2:
Email: [email protected]
Password: hello123
Explore the site! buy and sell on the site and watch the market reputation move !
It takes two to tango so make sure you have a friend to buy or sell an item!
You are welcome to create your own account and explore but if youd like to buy an item make sure to follow the steps to fund your account for FREE

github: https://github.com/RodrickVy/kommit