OpenTwin defines a canonical schema for property data — physical, financial, IoT, documents, and history — with owner-controlled consent built in from day one.
A bank, an insurer, and an AI assistant each need different slices of the same property's data. Today each of them builds a bespoke integration — and most just give up.
Every integration between these systems is custom-built from scratch. An AI assistant asking "when is my lift service due?" has no standard path to the answer. OpenTwin is the common language.
Computed from the property address via SHA-256 — self-issuable, no authority or fee required. Stable across ownership changes. Anchors a lifetime of lifecycle events.
// SHA-256 of NFC-normalised, lowercase address const hin = await computeHin(address, 'IN'); // → "hin:v1:IN:7e3cf2a148b9d0c4fb29e41a"
A bank or AI agent requests access with named scopes. The owner approves. EdDSA-signed JWT, 24-hour expiry, revocable in 60 seconds. No data moves without owner approval.
// Owner approves; JWT issued { "sub": "hin:v1:IN:7e3cf2a148b9d0c4", "aud": "bank:hdfc:mortgage-approval", "scope": "read:twin read:documents read:financial", "exp": 1761292800 // 24h }
One API call, one schema — regardless of which platform hosts the data. The bank's integration works on every compliant platform without a single line of platform-specific code.
const twin = await client.getTwin(homeId); // Same shape on every compliant platform: twin.home.hin // "hin:v1:IN:..." twin.documents // [sale deed, EC, RERA...] twin.aggregates.riskScore // 0–100
A consent token names exactly who gets what data, for how long, and for which purpose. Revocation propagates in 60 seconds. There is no implicit inheritance — an owner's token does not extend to a tenant's data.
The NestBrain ML model produces a 0–100 property health score from six factors: maintenance compliance, utility payment history, insurance coverage, asset condition, financial obligations, and document completeness.
RFC-0011 defines ten standard MCP tool shapes. Any AI framework — Claude, GPT-4o, Gemini — implements them once and works with every compliant platform. No bespoke connectors per platform.
// Claude using RFC-0011 MCP tools const result = await mcp.call('getPropertyTwin', { homeId: 'hin:v1:IN:7e3cf2a148b9d0c4', scopes: ['read:twin', 'read:devices'] }); // Works on SeekYourNest, any compliant platform const dueDate = result.devices .filter(d => d.type === 'elevator') .map(d => d.nextServiceDate); // → ["2026-11-15"] — Claude can now answer: // "Your lift service is due on 15 Nov 2026."
A public set of versioned specifications covering every aspect of the property data model. Apache 2.0. Contributions via GitHub pull request.
| RFC | Title | Category | Status |
|---|---|---|---|
| RFC-0001–0007 | Home Twin Core — home, assets, devices, documents, people, financial aggregates, passport | Base | Final |
| RFC-0008 | Home Identity Number — SHA-256 address hash, hin:// URI, DNS resolution, IANA draft | Identity | Draft |
| RFC-0009 | Premises Protocol — hospitals, schools, factories, malls, corporate offices, coworking | Sector | Draft |
| RFC-0010 | Consent & Data Exchange — OAuth-like flows, EdDSA tokens, 20-scope vocabulary, 60s revocation | Privacy | Draft |
| RFC-0011 | MCP Tool Registry — ten standard AI tool shapes for any LLM framework | AI | Draft |
| RFC-0012 | Security Model — Ed25519, AES-256-GCM, HKDF key derivation, ISO/IEC 27001 Annex A | Security | Draft |
| RFC-0013 | ISO Alignment — BIS India, JTC 1/SC 41, W3C CG, IETF submission roadmap | Governance | Draft |
| RFC-0014 | Home Financial Protocol — home bank account, credit score 0–850, mortgage, ISO 20022 | Finance | Draft |
| RFC-0015 | Verifiable Credentials — did:opentwin DID method, W3C VC 2.0, SD-JWT, EUDI Wallet | Identity | Draft |
| RFC-0016 | Home Lifecycle — 7 states, 12 events, HMAC-chained tamper-evident event log | History | Draft |
| RFC-0017 | OpenTwin Query Language (OQL) — declarative JSON queries, 11 operators, date variables | Query | Draft |
| RFC-0018 | Community Twin — housing societies, shared infrastructure, machine-readable bylaws | Community | Draft |
| RFC-0019 | Anti-Fraud & Duplicate HIN Resolution — challenge protocol, three conflict classes | Trust | Draft |
| RFC-0020 | Webhook Event Subscription — HMAC-signed delivery, 14-event catalog, retry schedule | Events | Draft |
| RFC-0021 | Rental & Tenancy — tenancy lifecycle, tenant consent isolation, portable rental credit score | Tenancy | Draft |
| RFC-0022 | Smart City Aggregate API — k-anonymity ≥50, differential privacy noise, municipality OAuth | Urban | Draft |
Query maintenance compliance, valuation history, and ownership chain with one API call. The same integration works across every compliant platform.
IoT device status, maintenance records, and claims history — with owner consent. Risk scores update in real time. Pilot results: up to −15% premium for very_low band.
RFC-0011 defines ten MCP tool shapes. One implementation works on every compliant platform.
Hand over the digital twin at possession. HMAC-chained lifecycle provides an immutable audit trail from groundbreaking to registration.
Add HIN as a secondary column on title records. Three adoption tiers from a simple string to a W3C Verified Issuer. k-anonymity ≥50 for urban aggregate queries.
Implement OpenTwin once. Your product works with every compliant platform. Level 1 conformance is free and self-attested. 2–4 weeks to go live.
22 RFCs in draft. Conformance suite available. Become a founding adopter and shape what v1.0 looks like.