NestCode defines a machine-readable digital twin for every building — a permanent NestCode ID, a 0–1000 NestScore™, and 42 open RFCs governing everything from Khata records to AI agent tooling.
// NestCode Twin · RFC-0001 · v0.3 { "nestcode_id": "hin:v1:IN:7e3cf2a148b9d0c4c54fa831", "address": { "unit": "4B", "building": "Tower C, Prestige Park", "locality": "Indiranagar", "city": "Bengaluru", "pincode": "560038", "country": "IN" }, "nestscore": { "total": 812, "band": "excellent", "factors": { "maintenance": { "score": 287, "weight": 0.35 }, "financial": { "score": 228, "weight": 0.25 }, "documents": { "score": 164, "weight": 0.20 }, "assets": { "score": 87, "weight": 0.12 }, "governance": { "score": 46, "weight": 0.08 } } }, "documents": { "count": 9, "verified": 7, "expiring_soon": 1 }, "assets": { "count": 12, "critical_overdue": false }, "schema_version": "0.3", "last_updated": "2026-10-23T14:32:00Z" }
| Weight | Factor | Source RFCs |
|---|---|---|
Maintenance Compliance AMC fulfilment rate, work order SLA adherence, preventive maintenance schedule, asset condition index. The single largest factor — chronic deferred maintenance destroys building value. |
RFC-0002 RFC-0030 |
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Financial Obligations Maintenance charge payment history, utility dues, outstanding penalties, escrow balance, sinking fund contributions. Property-level credit track record. |
RFC-0006 RFC-0014 |
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Document Completeness Sale deed, RERA cert, OC, building plan approval, insurance policies, Khata/Patta, encumbrance certificate. Weighted by expiry proximity and document criticality tier. |
RFC-0004 RFC-0037 RFC-0038 |
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Asset Condition IoT sensor health, last-service age, warranty status, energy efficiency rating. Devices past calibration date penalise this factor automatically. |
RFC-0002 RFC-0003 |
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Governance Compliance Society poll participation, AGM attendance, bylaw adherence, board election engagement. Introduced in NestScore v2.0. |
RFC-0023 RFC-0018 |
| RFC | Title & Description | Category |
|---|---|---|
| RFC-0001 | Home Twin Entity Base entity schema: unit, building, society, geolocation, lifecycle state. Foundation for all other entities. | Core Schema |
| RFC-0002 | Asset & Maintenance Inventory Lifts, pumps, generators, HVAC — AMC records, service history, condition index, failure probability score. | Core Schema |
| RFC-0003 | IoT Device Registry Sensors, controllers, meters. Firmware version, calibration date, last-read telemetry, alert thresholds. | Core Schema |
| RFC-0004 | Document Schema 28 document types: sale deed, title deed, RERA cert, OC, CC, NOC (bank/fire/airport), building plan, insurance, survey, EC, Khata, Patta. | Documents |
| RFC-0005 | Resident & People Directory Residents, owners, tenants, authorised persons. PII isolation: only hashed IDs in the twin; PII lives in consent-gated identity store. | Core Schema |
| RFC-0006 | Financial Aggregates Maintenance charge history, dues ledger, sinking fund balance, escrow, penalty accrual. ISO 20022 message shapes. | Finance |
| RFC-0007 | Property Passport Signed portable credential anchored to NestCode ID. Contains NestScore™ snapshot, key document hashes, and lifecycle state at issuance. | Core Schema |
| RFC-0008 | NestCode ID SHA-256 of NFC-normalised address. Format: hin:v1:{CC}:{32hex}. Self-computable offline. DID subject for RFC-0015. | Identity |
| RFC-0010 | Consent & Data Exchange EdDSA-signed consent tokens, 20-scope vocabulary, 60-second revocation, purpose-bound delegation. GDPR / DPDP compliant. | Privacy |
| RFC-0011 | MCP Tool Registry 10 standard AI tool shapes for property context. One implementation serves Claude, GPT-4o, Gemini, and other MCP-compatible agents. | AI |
| RFC-0012 | Security Model Ed25519 signatures, AES-256-GCM at rest, HKDF key derivation, HMAC audit log chaining. ISO 27001 Annex A mapping. | Security |
| RFC-0014 | Home Financial Protocol & NestScore™ The NestScore™ 0–1000 algorithm: 5 weighted factors, band definitions, ISO 20022 payment integration, escrow standard. | Finance |
| RFC-0015 | Verifiable Credentials did:opentwin DID method, W3C VC 2.0 conformant, SD-JWT selective disclosure, EUDI Wallet compatible. Property certificates as VCs. | Identity |
| RFC-0016 | Home Lifecycle 7 lifecycle states (construction → decommissioned), 12 transition events, HMAC-chained immutable log for regulator access. | History |
| RFC-0017 | NestCode Query Language (NQL) Declarative JSON query language for property data. 11 operators, date variables, cross-entity joins. Reference implementation in TypeScript. | Query |
| RFC-0018 | Community Twin Housing society entity: shared infrastructure, machine-readable bylaws, financial roll-up across all units, bulk consent delegation. | Community |
| RFC-0019 | Anti-Fraud & Duplicate NestCode ID Resolution 3 conflict classes (address ambiguity, fraudulent twin, split parcel), arbiter protocol, challenge/response with geocode proof. | Trust |
| RFC-0020 | Webhook Event Subscription HMAC-SHA256 signed push events, 14-event catalog, exponential backoff retry, at-least-once delivery, event replay by cursor. | Events |
| RFC-0021 | Rental & Tenancy Protocol Lease lifecycle (draft → active → terminated), tenant PII isolation, portable rental credit score, KYC evidence linking. | Tenancy |
| RFC-0022 | Smart City Aggregate API Municipality-facing API with differential privacy (ε=0.1) and k-anonymity ≥50. Area-level NestScore distribution, maintenance benchmarks. | Urban |
| RFC-0039 | OpenTwin Wire Protocol (OWP) Binary framing over WebSockets — 17 message types, consent-native subscribe flow, Ed25519 attestation, LZ4 compression, incremental RFC 6902 patches. The real-time sync layer for home digital twins. | Protocol |
| RFC-0040 | Home as Financial Entity HomeBankAccount schema (SAVINGS/CURRENT/ESCROW/MAINTENANCE_FUND), HomeWill financial clauses, Home as counterparty for insurance + escrow. India PMLA / UAE CBUAE regulatory alignment. | Finance |
| RFC-0041 | Inter-Society Transfer Protocol Twin portability when property changes hands. Dual-admin approval, consent inventory handoff, 14-day timeouts, Ed25519-signed Transfer Package, 30-day HMAC-chained audit log. 10-year legal retention. | Transfer |
| RFC-0042 | Home Will Protocol Beneficiary schema (fractional shares, KYC-linked), executor designation, death certificate trigger, Temporal probate workflow. India Succession Act + UAE Sharia / DIFC dual jurisdiction. | Legal |
| RFC-0043 | OpenGuild — Guild Identity Protocol (GID) Universal verifiable identity for every construction and service professional. GID format: GLD-{TRADE}-{STATE}-{YEAR}-{NNNNNN}. 16 trade categories (BLDR, ARCH, CIVC, STRC, INTR, PLMB, ELEC, CRPN, PNTR, TILR, MSNR, LNDS, SOLR, HVAC, VSTU, OTHR). Linked to RERA, review aggregation, trust scoring, and OpenTwin HIN provenance chain. Companion standard to OpenTwin. | Professionals |
| RFC-0023 | Society Governance Protocol Polls, resolutions, AGMs, board elections, quorum tracking. Results HMAC-chained, verifiable by court or regulator. | Governance |
| RFC-0024 | Facility & Amenity Booking Pool, gym, clubhouse slot management. Capacity limits, cancellation windows, maintenance blackout periods, AI booking via MCP. | Facilities |
| RFC-0025 | Gate Pass Protocol Visitor auth, pre-approved EdDSA-signed QR, contractor passes, delivery codes. AES-256-GCM offline cache (20-min TTL). | Access |
| RFC-0026 | Parcel & Delivery Management Carrier integration, last-mile custody chain, locker schema, OTP-verified collection, return-to-sender flow. | Ops |
| RFC-0027 | Emergency & Safety Protocol SOS with response tracking, evacuation headcount schema, first-responder data feed (floor plan + live occupancy), sensor triggers. | Safety |
| RFC-0028 | Vehicle Registry & Parking Resident and visitor vehicles, parking slot assignment, EV charging sessions (kWh + billing), enforcement log, carbon credit links. | Mobility |
| RFC-0029 | Helpdesk & Complaint Lifecycle Complaint entity, SLA breach tracking, work order linking, resolution evidence hashes, satisfaction score. | Ops |
| RFC-0030 | Predictive Maintenance & NestBrain ML-driven maintenance schedule, failure-probability model output, community benchmarks, AI-generated ops digest. Python + TS parity. | ML / Ops |
| RFC-0031 | Staff & Workforce Protocol Shift schedules, BGV credential (W3C VC with bar council or police ref), incident assignments, access control linkage. | Workforce |
| RFC-0032 | Community Marketplace Resident-to-resident listings, service exchange, event RSVPs, seller verified via twin identity, no PII in listing. | Community |
| RFC-0033 | Pet Registry Registered pets with microchip ID, vaccination records, area/lift access permissions, vet visit log. Linked to resident unit twin. | Registry |
| RFC-0034 | Property Handover Protocol Builder-to-society transition: snag list with photo evidence hashes, defect liability period tracking, OC linkage, common-area inventory. | Handover |
| RFC-0035 | Utility Metering Per-unit energy, water, and gas metering. Smart meter integration protocol, reading reconciliation, carbon credit schema. | Energy |
| RFC-0036 | Notification & Subscription Schema Standardised taxonomy for 40+ property event types. AI agent subscription via RFC-0011. Delivery: push, webhook, and MCP stream. | Events |
| RFC-0037 | Legal & Encumbrance Registry Title chain of ownership, encumbrance certificate (EC), mortgage/charge lien, power of attorney, advocate-attested documents (bar council ID + digital signature), notarisation. | Legal |
| RFC-0038 | Municipal Records & Revenue Khata (Karnataka), Pattas (Tamil Nadu), property tax assessment ID, NA order, zone classification, FSI/FAR entitlement, change of land use (CLU), building completion certificate. | Municipal |
SHA-256 of the geocoding-normalised address. Format: hin:v1:{CC}:{hex[0:32]}. Anyone with the address can verify any NestCode ID without contacting a server or creating an account.
Designed for T1 (SQL column in any property system) → T2 (printed on title deeds) → T3 (W3C Verified Issuer programme with governments).
hin:v1:IN:{32hex} — stored in the property record, printed on documents.POST /opentwin/nestcode-id/resolve for production-grade server-side computation.| Level | Name | Minimum requirements | Cost | Unlocks |
|---|---|---|---|---|
| L1 | Self-Attested | RFC-0001–0007 conformant. Run open-source conformance suite. Self-declare on GitHub. | Free | NestCode™ Compatible badge |
| L2 | Peer-Reviewed | RFC-0008, RFC-0010, RFC-0012 conformant. Review by two existing L2+ members. Public registry listing. | Free + peer time | Public registry entry |
| L3 | Audited | All core RFCs + NestScore™ implementation. Third-party audit required. Annual re-certification. | Audit fee | Bank + insurer integrations |
| L4 | Governance Steward | L3 status + at least one merged RFC contribution. RFC vote participation. | L3 + membership | Co-author future RFCs |
OpenGuild is a companion open standard to OpenTwin. Just as every home has a HIN, every builder, architect, and tradesperson gets a GID (Guild Identity) — a permanent, verifiable credential that aggregates RERA compliance, project provenance, and buyer reviews into a single public URL. Format: GLD-{TRADE}-{STATE}-{YEAR}-{NNNNNN}
Every renovation or construction project is anchored to the home’s HIN via a GID-signed record — a tamper-evident chain of who built, renovated, or serviced the property.