EarnX

EarnX: get paid when you ship, not when your buyer pays.

Why I'm building it: my mother, Mama Dora, grows cassava and other crops in Delta State, Nigeria. Just after a harvest my father had a stroke, and the hospital needed money that week. Her harvest was worth more than the bill, but buyers pay 30 to 90 days after delivery. We sold crops cheaply, then borrowed from a bank, and the fees and interest bankrupted us. She is not alone: in 2024, $74-92B of trade finance requested by African businesses went unmet, and 37% of applications were rejected (African Development Bank).

What EarnX does

• Exporters sign in with a passkey (a ZeroDev smart account with sponsored gas: no wallet app, no seed phrase), upload the invoice and shipping documents to IPFS, and submit. The documents' hash goes on-chain.

• An automated pre-screen checks the documents against the on-chain hash, quantity x price against the total, the price against World Bank benchmarks, and every invoice on both chains for duplicates. A risk engine written in Rust on Arbitrum Stylus then sets the APR and the advance on-chain from a published formula.

• Investors fund in Paxos USDG (or Circle USDC). The transaction that completes the funding pays the exporter up to 90% of the invoice and puts 1% into a first-loss reserve that protects investors.

• The buyer repays and investors claim principal plus yield, pro-rata. Every verified invoice mints a soulbound record (ERC-5192, on-chain SVG) to the exporter: a credit history that belongs to them.

Who stands behind an invoice

• Exporters who haven't verified their business are approved automatically only up to $1,000 per invoice. Verification is an on-chain registry (a role on the protocol contract) granted after a reviewer checks the business against its national registry; the request is encrypted before it is stored.

• Above $1,000 the buyer must sign a statement built from the invoice's on-chain facts: they ordered the goods, the invoice is genuine, and they will pay the EarnX contract. Wallet and passkey signatures (ERC-1271/6492) are checked, and the signed statement is pinned to IPFS and shown to every investor.

• The same documents, or the same invoice number for the same buyer, cannot be financed twice on either chain. Over-invoicing against World Bank prices is rejected.

Cost: a 60-day invoice costs about 7% of the money received at a Nigerian bank (29.2% a year, CBN August 2026, plus up to 2% in fees and collateral) versus about 3% on EarnX, with no collateral.

Built with: Robinhood Chain, Arbitrum Sepolia, Arbitrum Stylus (Rust), Paxos USDG, Circle USDC, ZeroDev passkeys and paymaster, OpenZeppelin 5.7, Alchemy, IPFS via Pinata, World Bank Pink Sheet, Foundry (29 tests including fuzzing), React and viem.

Proof: the demo invoice (#19 on Robinhood Chain testnet) went through every step on-chain. Funding tx: https://explorer.testnet.chain.robinhood.com/tx/0xf0330a8a0398ac2c4bc9c0f381d916d7922513921cd01b02fbd597692967be3e (the investor's 40.5 USDG in, the exporter's 40.095 USDG out). Repayment tx: https://explorer.testnet.chain.robinhood.com/tx/0x4995f7ef55885c70fef66b18b4760cca4f7bca2b81cccb4dd2d212e28b0311a5

App: https://earnx-app.vercel.app | Code: https://github.com/big14way/earnx

Status: testnets only; the contracts are not audited. Invoices marked "sample" are fictional and were seeded to show the product.

EarnX started earlier as a Mantle prototype (tagged pre-buildathon in the repo) and as a separate Arbitrum prototype entered in Arbitrum Open House NYC. For Singapore we rebuilt it from scratch in github.com/big14way/earnx; every change since is at github.com/big14way/earnx/compare/pre-buildathon...main

During the buildathon we:

• Rewrote the contracts. EarnXProtocol: submit, verify by role or by an EIP-712 signature bound to the documents' hash, invest, automatic payout to the exporter, partial repayments, pro-rata claims, and defaults covered by a first-loss reserve that recoveries refill. EarnXInvoiceNFT: soulbound ERC-5192 trade records with on-chain SVG.

• Wrote a risk engine in Rust on Arbitrum Stylus that prices every invoice on-chain, deployed and activated it on both chains, and plugged it into the protocol.

• Wrote 29 Foundry tests including fuzzing, 6 Rust tests and CI, then deployed and source-verified on Robinhood Chain testnet and Arbitrum Sepolia with Paxos USDG (and Circle USDC on Arbitrum).

• Built a new app on live on-chain data: passkey accounts with sponsored gas (ZeroDev), IPFS documents, an automated pre-screen with World Bank price checks, deal sheets, exporter trade records and a live activity feed.

• Added the trust layer: business-verification limits from an on-chain registry, signed buyer confirmations (wallet or passkey, pinned to IPFS), and a duplicate check across both chains.

• Ran the whole lifecycle on-chain: 36 invoices across the two testnets and 5 repaid in full, so far samples and our own tests. Invoice #19 on Robinhood Chain shows every step, from submission to the investor's claim.

Not raised yet: EarnX is bootstrapped by the founder. Next we are looking for milestone grants and first-loss capital partners to run a pilot with exporters in Nigeria.