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PIN — Property Identification Number

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How properties exist as first-class identities on Leja

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What the PIN Is

Every physical property listed and verified on Leja receives a permanent Property Identification Number (PIN). It is the property’s identity — not the landlord’s identity, not the agent’s identity. The property itself has a record. The PIN is not a role. It is not a listing. It is the property. Format: PIN-NG-YYYY-XXXXXXXXXXX Example: PIN-NG-2026-F2H6N4T8W3V The PIN accumulates the full history of a property:
  • Maintenance events (what was reported, who fixed it, how long it took)
  • Tenancy history (how many tenancies, average duration — no tenant identities)
  • Condition record (inspection outcomes over time)
  • Dispute history (count and nature — no party identities)
  • Availability status (real-time)
  • Neighborhood trust score (aggregated from all Leja properties nearby)
The PIN follows the property through ownership changes. When a property is sold, the new owner inherits the PIN and its full history. They cannot reset it.

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Why the PIN Matters

Without a PIN, a buyer inspecting a property can only trust:
  • The agent’s description (potentially biased)
  • The landlord’s claims (self-reported)
  • Their own inspection (one-time, incomplete)
With a PIN, a buyer can see:
  • How many maintenance issues have been reported (and resolved or not)
  • How long previous tenancies lasted (stability signal)
  • Whether the property condition consistently improved or declined
  • Whether the neighborhood trust score is high or declining
  • What the property’s current availability status is
This destroys the information asymmetry that has always favored sellers over buyers in the Nigerian property market.

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The Three-Way Linkage Model

Every PIN is anchored to three identity nodes simultaneously:

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Node 1 — Property Owner (RIN)

The verified property owner’s personal RIN is the primary anchor. It is set at PIN issuance and updated if the property is sold. Every ownership transition creates a permanent ownership history node. 
PIN-NG-2026-F2H6N4T8W3V
  └── OWNER: RIN-NG-2026-A7B3K9M2Z5Q (current owner)
      └── Previous owners: [ownership history chain]
The owner’s RIN and the PIN are permanently linked. If the owner’s identity is later found to be fraudulent, the fraud is traceable through the PIN record. The link is immutable.

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Node 2 — Listing Agent (Personal RIN)

When an agent lists a property on Leja Professional, their personal RIN is attached to the PIN as the listing agent node. This is distinct from the owner node — the agent may not own the property. 
PIN-NG-2026-F2H6N4T8W3V
  └── CURRENT LISTING AGENT: RIN-NG-2026-B4C7P1Q9X2M (agent's personal RIN)
Rules:
  • Only one agent can hold the current listing node at a time
  • When an agent withdraws a listing or the property is sold, their listing node becomes historical — the next listing agent creates a new current node
  • The listing agent takes professional responsibility for the accuracy of what they enter on that listing

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Node 3 — Listing Organisation (BRN, if applicable)

If the listing agent is employed by an organisation, the organisation’s BRN is also attached as a node alongside the agent’s personal RIN. 
PIN-NG-2026-F2H6N4T8W3V
  └── CURRENT LISTING AGENT: RIN-NG-2026-B4C7P1Q9X2M
  └── LISTING ORG: BRN-NG-2026-C4E8L2P7R1X (agent's employer at time of listing)
Solo agent listings: Only the agent’s personal RIN is attached. No BRN node. Org agent listings: Both the personal RIN and the BRN are attached simultaneously. This means both the individual and the firm have witnessed professional accountability for what is listed under their credentials.

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Historical Listing Events — The Property’s Professional Record

Every time an agent lists, relists, sells, or withdraws a property, a permanent PropertyListingEvent is created on the PIN. 
PropertyListingEvent record:
  agentRinId     — personal RIN of the agent involved
  orgBrnId       — BRN of the org (null for solo agents)
  eventType      — LISTED / RELISTED / SOLD_BY / WITHDRAWN
  listedAt       — timestamp
  endedAt        — when this listing period ended (null if current)
Event types: 
LISTED     — Agent listed this property for the first time (or after a gap)
RELISTED   — Property re-listed by a new or the same agent after a period off-market
SOLD_BY    — Agent facilitated the sale of this property
WITHDRAWN  — Listing withdrawn by agent or owner without a sale
Over time, the PIN accumulates a full professional trail:
  • Which agents have ever listed this property
  • Which organisations have ever represented it
  • Whether it has been listed and withdrawn repeatedly (red flag signal)
  • Who sold it and when
  • How many agents have handled it across its history
This creates accountability that did not previously exist in the Nigerian property market. A property that has been listed by ten agents in two years, each withdrawing within weeks, carries a behavioral signal no single agent can erase.

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Real-Time Status

The PIN has a current availability status visible to all parties: 
AVAILABLE
  The property is vacant and open for viewings and offers.
  No active tenancy. No holding deposit received.

UNDER_OFFER
  A holding deposit has been received and witnessed by Leja.
  The property is not available for competing offers.
  Any second agent attempting to collect a deposit is flagged.
  The double-letting fraud prevention system is active.

OCCUPIED
  An active tenancy is in progress.
  Lease signed, payment schedule established in the record layer.
  The property will return to AVAILABLE on lease end.

SHORT_LET_ACTIVE
  A current short-let guest is checked in (Leja Stay).
  The property returns to AVAILABLE on check-out.
The double-letting fraud prevention: When a property moves to UNDER_OFFER, this status is immediately visible to ALL parties querying that PIN. If a second agent attempts to collect a deposit on the same property, the system flags it. If two parties claim to have paid, the record layer shows who paid first, when, and to which agent. The fraudulent agent cannot deny it — the record is permanent.

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What the PIN Accumulates

Public standard (visible to all Leja parties without login):
  • Verification tier (PROVISIONAL, COMMUNITY_VERIFIED, INSPECTED)
  • Building age (banded: pre-2000, 2000–2010, 2010–2020, post-2020)
  • Previous tenancy count (no tenant identities)
  • Average tenancy duration
  • Maintenance history (issue types and resolution times — no party names)
  • Last inspection date and overall condition rating
  • Utility connection status (electricity, water, waste — verified or claimed)
  • Dispute history (count and category — no party identities)
  • Rent band history (rising / stable / falling — not exact amounts)
  • Known recurring issues log
  • Neighborhood trust score
  • Real-time availability status
  • Number of distinct listing agents over the property’s history (banded)
With owner consent:
  • Exact previous rent amounts
  • Detailed maintenance reports (job descriptions, outcomes)
  • Exit inspection photos (anonymized — no tenant identities visible)
Never visible:
  • Previous tenant identities
  • Exact rent unless owner consents
  • Landlord personal details beyond verification status
  • Any service provider identity from maintenance jobs
  • The agent’s commission or fee for the listing

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PIN Issuance

Who can create a PIN: The verified property owner — directly, or via an agent acting on their behalf. If an agent initiates the PIN creation, the owner must explicitly confirm it. The PIN is issued linked to the owner’s personal RIN. Minimum owner requirement: The owner must have at least NIN_VERIFIED personal RIN before they can create a PIN. This is stricter than the old PHONE_VERIFIED minimum — property ownership claims require confirmed identity. NIN_VERIFIED is required for all property types (residential and commercial). At issuance, the system creates:
  • PIN at PROVISIONAL tier
  • Ownership node linking PIN → owner’s personal RIN
  • If agent initiated: listing agent node linking PIN → agent’s personal RIN (and BRN if org staff)
  • TrendEvent on the owner’s RIN: PROPERTY_LISTED
  • TrendEvent on the agent’s RIN: PROPERTY_LISTING_CREATED (if agent initiated)
  • PropertyListingEvent record: LISTED
Digital verification stack (no physical inspection by Leja): 
Step 1 — Owner Identity
  NIN verification via NIMC KYC partner (NIN_VERIFIED tier required)
  The property owner's identity is confirmed as a real person

Step 2 — Ownership Claim
  Owner uploads one of:
    Certificate of Occupancy (C of O)
    Deed of assignment
    Governor's consent
    Survey plan
    Allocation letter
  Leja stores the document, records its hash
  Leja witnesses the CLAIM — not title authenticity
  If the claim is fraudulent, the fraud is permanent in the record
  Liability for false ownership claims stays with the owner

Step 3 — Property Existence Signal
  Address geocoded against public mapping data
  Street View baseline image captured and stored as reference
  This is a best-effort signal — Nigeria's mapping data is sparse
  A non-matchable address does not block issuance (flags it as UNMAPPED)

Step 4 — Community Signal (optional, upgrades tier)
  Any existing Leja-verified user can attest: "I know this property
  exists at this address — I have been there."
  Each attestation from a verified user upgrades the verification tier
PIN verification tiers: 
PROVISIONAL
  Owner identity verified (NIN_VERIFIED), ownership document uploaded
  Sufficient for Leja Professional listing and Leja Stay hosting

COMMUNITY_VERIFIED
  PROVISIONAL + at least 1 independent verified attestation
  Stronger signal for potential tenants and buyers

INSPECTED
  Milestone Wave 4 — third-party inspection partner (not Leja staff)
  Highest tier — physical condition confirmed by independent party

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Maintenance Leja Professional and the Bidirectional Connection

Every service job completed through Resident on a property automatically feeds that property’s maintenance history in Leja Professional. This means:
  • A landlord does not need to manually log maintenance events
  • Every Resident-processed job creates a permanent record on the PIN
  • The property’s witnessed maintenance history grows every time a plumber, electrician, or painter processes a job through Resident
This is the indirect but critical connection between Resident’s service participation loop and Leja Professional PIN management. The records flow automatically.

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PIN and Leja Stay

For a property to be listed on Leja Stay (short-let), it must have a PIN at minimum PROVISIONAL verification tier. The Leja Stay listing references the PIN. Every short-let booking creates a TrendEvent on the PIN. Every post-stay rating updates the PIN’s condition history. The property’s short-let reputation is part of its permanent record.

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PIN in the Trust Graph

The PIN is a first-class node in the Trust Graph. A tenancy transaction touches the PIN directly:
  • Tenant’s personal RIN (Track 1 event added)
  • Owner’s personal RIN (owner behavior witnessed)
  • Agent’s personal RIN (Professional Record updated, PropertyListingEvent updated)
  • Org’s BRN (if applicable)
  • PIN (tenancy count, duration, condition, maintenance all updated)
The Trust Graph lens matrix (View 4) governs what each party can see when they query a PIN. See 02_Trust_Architecture/02_trust_graph_lens_matrix.md.