People lose things all the time, and “contact me if found” stickers are fragile: messages get ignored, rewards aren’t trusted, and there’s no neutral way to escrow money or prove someone actually had the item. Centralized “lost & found” apps solve part of this but require accounts, KYC, and trust in a company.

LAF is a fully onchain, QR/NFC-friendly lost-and-found system: the owner sets a reward in tokens, the finder proves possession via a cryptographic secret, and funds/fees/charity splits are handled by contracts. The finder gets an instant partial payout on “Found,” the rest on “Returned,” after getting in touch with the owner via ethemeral encrypted chat. Contracts have built-in cooldowns, anti-replay, and non-return resolution. Everyone gets non-transferable badges (SBTs) that build a public trust score over time.

What people use it for

Tag keys, bags, bikes, instruments, laptops, wallets, pet collars, etc. with a QR/NFC that resolves to the item page.

Post an onchain bounty that is escrowed—no awkward negotiations, no “will they pay me?” doubts.

Prove finding via a commit-reveal signature tied to the item and chain; no photos or private chats needed.

Auto-donate a slice to a charity and a platform fee (configurable), creating positive-sum incentives.

Earn SBT trust for returning items (or lose it for non-return), making reputation portable across apps.

(Backed by a gas-efficient factory + per-item clone, cryptographic “found” proof, fee splits, cooldowns, and SBT trust mechanics in the contracts. )

1. Anti-replay + lifecycle safety for “Found.”
   Early prototypes were vulnerable to replay across lifecycles. I introduced an item cycle and a secret-anchored proof (LAF.found(secretHash, signature) ↔ LAFItem.found) so a past “Found” can’t be reused after states change; audit tests cover replay and lifecycle transitions.

2. Partial payouts + fee math without foot-guns.
   On “Found,” the contract pays immediateRewardBps and defers the remainder to “Returned.” I centralized fee math (treasury, delegate, charity) with min/max BPS bounds and cool-downs (found/return/non-return) in Config/ConfigOwnable to prevent bad updates or underflow/overflow edges.

3. Smooth approvals + smart-wallet UX.
   On the front end, LostButton wires a pre-tx approval trigger (useApproval) into a generic TxButton that auto-simulates, writes, and waits for receipts across EOAs & Privy smart wallets (fund/embedded export supported). This removed failed-tx friction and made the “Lost” path one click.

4. Location without doxxing.
   We encode positions as geohash strings, show them on Leaflet, and only reverse-geocode in the modal; no PII is stored onchain, only the geohash string and timestamps.

https://github.com/guy-do-or-die/laf

https://www.laf.is/

Trustless recovery economics: Rewards escrowed in ERC-20, instant partial payout on “Found,” final settlement and fee/charity splits on “Returned.” No DMs needed, no “will they pay?” risk.

Portable, onchain reputation: Non-transferable ERC-1155 badges (Registered/Lost/Found/Returned/Support) + thumbUp/thumbDown accumulate as a public trust score per address.

Composability from day one: Factory clones per item, clean events, a subgraph, and small wagmi codegen hooks so wallets, tag vendors, or venues can embed flows quickly.

Alpha proof: You can register, set reward + geohash, call lost/found/returned, see payouts/splits, and message via Waku from the live React app. All actions are verifiable on Base (addresses in config).

Primary: people with real-world items worth recovering (keys, bikes, instruments, laptops, pet collars) and communities/venues where items are commonly misplaced (campuses, gyms, co-working spaces, clubs).

Secondary: tag vendors (QR/NFC), rental fleets, event organizers, wallets/dapps that want to surface “has returned N items” as a credibility signal.

Why we believe this fit: hallway tests and dogfooding show the “no haggling, no custody risk” flow is faster and less awkward; the public trust badges make returns socially visible and integrate easily into other Base apps via the subgraph.

Mainstream trackers & QR tags

• Tile / Life360 Tile Labels — https://www.life360.com/en-eu/tile-trackers/how-tile-labels-work
• Apple AirTag — https://www.apple.com/airtag/
• Samsung SmartTag — https://www.samsung.com/smartthings/find/
• Dynotag — https://dynotag.com/
• ReturnMe — https://return.me/

LAF vs. them

• Escrowed, automatic payouts (no trust in a company or DM negotiation).
• Cryptographic proof of possession via secretHash/signature + lifecycle cycle (replay-hard).
• Onchain reputation & composability (ERC-1155 badges, thumbs, events, subgraph) others can read.
• Charity & delegate fees are native and auditable; great for community or brand activations.
• Supports DIY tagging at no cost
• Social element of infinite treasure hunt