The need

Diaspora families lose savings to unfinished or fake construction back home. A nurse in London sends money for two years on the word of a relative or a contractor, and a cousin's visit reveals walls to the windows where a roof was promised. Distance makes checking impossible, and asking too often feels like accusing family.

What exists and what is new

Closest: a few local services and milestone-payment apps for contractors, such as Ownkey in Ghana and Kolonell, plus diaspora project managers, quantity surveyors and lawyers who hold funds, and the usual WhatsApp videos from relatives. Some of these already offer staged payments or site visits; check their current offerings, as this is described from public information. New: every stage's money sits in escrow and is released only after two independent checks agree: an AI review of geotagged, timestamped walkthrough video against the bill of quantities and the previous video, and a booked visit by an independent inspector. Discrepancies freeze only the disputed amount and run as a case with evidence.

The data it runs on

The contractor's site videos with device GPS and timestamps (recorded in the app, so they cannot be old clips), the bill of quantities and drawings, the inspector's checklist report with photos, and the escrow ledger. Each stage compares what was paid for, what the video shows, and what the inspector saw.

1. The mission

Building a home back home should be a joy, not a gamble. Build Back Home lets families abroad build with confidence, pay contractors fairly and quickly, and watch the house rise together.

2. Why people can't resist it

• Seeing is believing. A fresh walkthrough every week, with the location and time stamped, turns anxiety into anticipation.
• No awkward calls. The system does the checking, so family relationships stay intact.
• A story to share. The photo diary becomes the family's favourite thread: every stage is a small celebration.

3. How it works for real

1. Capture: the contractor records in the app; GPS, timestamp and device integrity are signed at capture, and uploads outside the site fence are rejected.
2. Vision: a video model pipeline (Gemini class video understanding or GPT vision via OpenRouter on sampled frames) estimates block courses, detects trusses, sheets, openings and material stocks, and compares with the previous video.
3. Matching: a frontier LLM (Claude) maps findings to bill of quantities lines and writes a plain summary; plain code computes percentages and the release amount.
4. Inspection: a marketplace of licensed independent inspectors, paid per visit from the escrow, files a checklist report with photos.
5. Escrow: USDC on Base held in a contract per stage; the owner signs in with email (smart wallet, crypto invisible, gas sponsored) and funds by card or bank; the contractor is paid out to mobile money or bank in cedis through an off-ramp partner.
6. Cases: disputes freeze only the line item, collect evidence from both sides, and resolve with inspector confirmation.

4. Cost per use

AI review of one 2 minute walkthrough (sampled frames plus summary): $0.05 to $0.15. Inspector visit: about GH₵ 600 to 900 ($50 to $80), paid from the escrow per stage. Escrow and payout fees: about 0.5% to 1% per release, gas sponsored. For a GH₵ 450,000 house in 4 to 6 stages, the platform costs the owner roughly 1.5% plus inspections. Free: one project with video checks; paid: inspections and escrow fee per release. A solo builder needs a local partner for inspectors and off-ramp.

5. Growth loop

Family members are invited to the photo diary and see how safe the process is, and many of them are planning their own builds. Good contractors earn a verified track record and bring their next diaspora clients onto the platform. Hometown associations in London, Toronto and Houston share it in their groups.

6. Risks and guardrails

• AI estimates are never the only check: money moves only when the inspector agrees.
• Inspectors are independent, rotated, and rated; they cannot be chosen by the contractor.
• Holds are limited to the disputed line, so contractors are not starved of cash for honest work.
• Escrow funds stay in the owner's control until approval; every release needs the owner's tap within set limits.
• Land title and permits are outside the app's checks; the app points owners to a lawyer for those.

7. MVP build order

1. One city (Kumasi), three contractors, five inspectors, manual matching.
2. In-app video capture with GPS and timestamp, plus a simple frame review.
3. Stage escrow with email login and owner approval.
4. Discrepancy case flow with partial holds.
5. Family photo diary and invites.

People, contractors, inspectors, amounts and transaction hashes in this demo are fictional samples. Not financial or legal advice.