What we're building

Proof of Care — The Technology

What we are building — and why it works.

A field worker in rural Tanzania sends a WhatsApp video. A donor in Melbourne funds a surgery. A surgeon gets paid the moment a child is verified home. No forms. No invoices. No bank accounts required. No understanding of technology needed by anyone on the ground.

WhatsApp → AI verification → YouTube → Blockchain → Payment  ·  Runs 24/7 on any mobile phone
The simple version first

Three videos. One WhatsApp number. Automatic payment when the child is home.

Nobody in this system needs to understand how it works. Let sends a video. Eli sends a video. The nurse sends a video. A piece of software called a webhook receives every message and automatically handles everything else — the record keeping, the fraud checks, the YouTube upload, the blockchain entry, and the payment.

The technology is invisible. The outcome is real.

How it flows
Let's phone
Tanzania
Films a 60-second video. Sends it to one WhatsApp number.
Child's face, visible condition, Let on camera, location, date. No form. No system. Just a video.
Meta
WhatsApp API
Receives the message and forwards it to the POC server.
Meta's infrastructure — the same system that handles billions of WhatsApp messages daily.
POC Server
Railway
The webhook receives the video and runs all checks automatically.
Is Let registered? Is the GPS zone valid? Is this a duplicate? Downloads the video, extracts a frame, sends to AI.
OpenAI
Vision AI
AI analyses the video frame in under 2 seconds.
Is a face visible? Is this consistent with the claimed stage? Generates a face descriptor for duplicate detection. Quality score 1–10.
YouTube
Auto-upload
Video is uploaded to the POC YouTube channel instantly.
Unlisted — accessible via link but not searchable. Title auto-generated: "TZ-11156 — FIND VIDEO". Permanent, public record.
Base
Blockchain
Smart contract records the proof event. NFT piece minted to donor.
Permanent, tamper-proof, publicly auditable. Costs ~$0.001. USDC held in escrow. POC Coins issued to actor. Donor's 7-piece NFT gains one more piece.
Let's phone
Reply
Let receives a WhatsApp reply within 90 seconds.
✅ Child registered: TZ-11156
Your payment: $90 locked until child is home.
The donor's proof receipt

A 7-piece NFT that assembles as the child's journey progresses.

Every donor receives a digital receipt that updates in real time. It starts as an incomplete picture — one piece minted at each stage of the journey. When all seven stages are verified and the picture is complete, the smart contract releases payment to every actor simultaneously.

The complete NFT is the donor's permanent proof. Not a PDF. Not a report. A verifiable, on-chain record that their money reached a real person and produced a real outcome.

Stage 0
Find
Let finds the child
Stage 1
Plan
POC approves
Stage 2
Fund
Donor commits
Stage 3
Fix
Surgery done
Stage 4
Recover
Aftercare
Stage 5
Return
Child is home
Stage 6
Review
POC verifies
Complete
Paid ✓
NFT assembled

When the seventh piece drops, the picture completes. The smart contract releases payment to everyone simultaneously. The donor's NFT is now a permanent, verifiable receipt — on-chain, forever.

POC Coins — work tokens

POC Coins show actors their budget. They are not paid until the job is done.

When Let submits a proof video, he receives POC Coins showing his share of the budget — say $90 worth. He can see his money coming. But he cannot spend it, transfer it, or cash it out.

POC Coins are locked until the final verification is complete. If the chain breaks — if the child cannot be located, if proof fails, if the deadline passes — the coins are forfeited and the donor's USDC returns automatically.

When the outcome is verified, the coins burn and USDC is sent to every actor simultaneously. For Let in Tanzania, that arrives as an M-Pesa notification within minutes.

What POC Coins are
Conditional payment instruments. Non-transferable. Locked until completion. They show budget, not currency. The actor carries the risk — which is why they move fast.
What POC Coins are not
Not a currency. Not tradeable. Not a store of value. Not an investment. They are a locked promise to pay — redeemable only by the actor who earned them, only when the outcome is proved.
The technology stack

Seven proven technologies. One seamless system.

WhatsApp
Meta WhatsApp Business API — the interface every field worker already uses. Receives videos, sends replies. Works on any phone with basic mobile data. No app to install.
Server
Node.js webhook on Railway — the brain. Runs 24/7, receives every message, routes it to the right handler, replies within 90 seconds. No downtime, no office hours.
Database
PostgreSQL — stores all worker registrations, child records, trust scores, submission history, and payment logs. Fast, reliable, queryable by any government auditor.
AI
OpenAI GPT-4 Vision — analyses every video frame. Checks quality, confirms the right stage, generates a face descriptor for duplicate detection. Runs automatically on every submission.
Video
YouTube Data API — every proof video is uploaded automatically as an unlisted video with a standardised title. Permanent, accessible via link, auditable by anyone with the URL.
Blockchain
Base network (Coinbase L2) — the immutable record. Three smart contracts handle escrow, POC Coins, and the 7-piece NFT. Gas cost ~$0.001 per transaction. USDC payments settled in seconds.
Relay
Gelato Network — optional gasless transaction relay. At scale, removes the need for POC to hold ETH for gas fees. Contracts pay for themselves through the system fee.
The smart contracts

Three contracts. One outcome. Nobody controls the money except the proof chain.

The contracts run on Base — a public blockchain owned by nobody, auditable by everyone. Once deployed, even POC cannot change the rules. The funder's money is safe because the contract enforces it, not because POC promises to.

POCOutcome7.sol — the main contract
Manages the entire 7-stage lifecycle. Holds USDC in escrow. Accepts proof submissions at each stage. Enforces time limits. Releases payment when all stages are verified. Auto-refunds if deadlines pass.
POCCoin.sol — the work token
Mints locked POC Coins to actors at each stage. Enforces the non-transferable rule at the contract level — no code workaround possible. Burns coins and triggers USDC payment on completion. Forfeits coins if the chain fails.
POCJourneyNFT.sol — the donor receipt
Mints one ERC-1155 NFT piece to the donor at each verified stage. Tracks which pieces exist. When all 7 pieces pool together, mints the COMPLETE NFT — the permanent, verifiable proof receipt that lives on-chain forever.
Cost per outcome — all on-chain steps combined
7 stage proof submissions~$0.007
Payment release transaction~$0.001
NFT minting (7 pieces + complete)~$0.008
Total on-chain cost per child~$0.02
Fraud prevention — built in, not bolted on

Every actor is registered and rated. Trust builds over time. Fraud is structurally expensive.

A fraudulent submission earns nothing unless every subsequent stage in the chain is also fraudulent — a sustained, coordinated effort that costs more than it returns. The system makes honest behaviour structurally more valuable than dishonest behaviour.

New actor
Manual review of every submission. Full verification of every video. High scrutiny. Builds trust with clean cases.
Established actor
Automated checks. Spot reviews. Periodic in-person visits. More cases allocated. Better star rating. Higher earnings.
AI face matching
Face descriptors generated at FIND stage. Cross-matched on every subsequent video. Same child confirmed throughout the journey.
Verifier oversight
Independent verifiers are themselves rated. A secondary review layer checks verifier consistency. The system checks those who check the system.
Why it scales

The unit of delivery is identical at 10 cases or 10,000. No new bureaucracy required.

The same system that tracked the first surgery tracks the thousandth. The proof chain is the system. Adding more cases does not require more staff, more offices, or more reporting layers. It requires more actors — who are registered, rated, and paid automatically.

Scaling target
Hospitals in network1,000
Surgeries per hospital per year1,000
Cost per verified surgeryunder $1,000
Total outcomes per year1,000,000

The same system applies to flood relief, girls' education, veterans' mental health, and social housing. Different outcomes. Different actors. Different countries. Same proof chain. Same technology. Same result.

Every person did one thing.
Filmed what they did.

No forms. No invoices. No bank accounts. No understanding of technology. A field worker with a basic Android phone is the starting point of a chain that is auditable by any government, visible to any donor, and permanent on a public blockchain forever.

Operating in 3 countries, 2 more starting  ·  1,467 verified surgeries  ·  $1.2M delivered  ·  Every outcome on record