🔒PRIVATE BETA — This API is not yet open to the public. Access is by invitation only.
PROXIMITY VERIFICATION API · V1

Verify proximity.
Build trust.

The HorizonLink API lets you verify that a contact is physically present within a defined radius — authenticated by their phone's GPS, cross-checked with sensor data, and delivered to your server via signed webhook.

HOW IT WORKS

Four steps to verified presence

01
CREATE REQUEST
POST to v1-proximity-create with a target user ID, radius in metres, and optional minimum trust score.
02
USER IS NOTIFIED
The HorizonLink app notifies the target. They tap to respond — the app captures a fresh GPS fix and sensor readings.
03
SCORE IS COMPUTED
Server and client signals are combined: distance, GPS accuracy, speed, IP/GPS country, accelerometer, barometer.
04
WEBHOOK DELIVERED
A signed webhook fires to your server with the result, trust score (0–100), distance, and any flags.
WHAT YOU GET

Enterprise-grade signals, API-simple

📍
GPS VERIFIED
Haversine distance computed server-side. The client cannot fake a "within range" result.
🛡️
ANTI-SPOOFING
Mock-location detection, speed sanity checks, accelerometer variance, barometric altitude cross-check.
🌐
IP vs GPS COUNTRY
Server cross-checks the client IP country against the GPS-reported country. VPN use is flagged.
📊
TRUST SCORE 0–100
A composite score from all signals. Set a minimum threshold — only high-confidence verifications pass.
🔔
SIGNED WEBHOOKS
Results delivered via HMAC-SHA256 signed POST. Verify with your webhook secret.
🔑
SIMPLE AUTH
Single X-API-Key header. No OAuth dance. Keys generated in-app or here on the portal.
QUICK START

One request to start a verification

curl -X POST https://gjxpulfkxhpoghcsklsx.supabase.co/functions/v1/v1-proximity-create \
  -H "X-API-Key: hlv_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
    "target_user_id": "uuid-of-the-user",
    "radius_m": 100,
    "min_trust_score": 70,
    "webhook_url": "https://yourdomain.com/webhook"
  }'
PRICING

Start free, scale when ready

FREE
$0
forever
✓100 proximity requests / month
✓All anti-spoofing signals
✓Trust score (0–100)
✓Signed webhook delivery
✓API key in-app or portal
✓Auto-resets monthly
PRO
TBD
coming soon
✓Unlimited requests / month
✓Everything in Free
✓Priority support
✓SLA guarantee
✓Custom radius limits