Built for East Africa · Nairobi, Kenya

Device financing
infrastructure for
Africa's next billion

Enterprise-grade PAYG locking, billing, and fleet management for smartphones and IoT devices. M-Pesa native. SMS-first. Deployable from day one.

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Works with
Samsung Tecno Infinix Itel M-Pesa
9:41 ●●● 📶 🔋
🔒
Payment Required
Your weekly payment
is due to continue using this device
KES 350
Due today · Grace period ends in 2hrs
Payment KES 350 received 2d ago
Device unlocked via M-Pesa 2d ago
Payment reminder sent Today
✓ Unlocked in 1.8s
🔐 8-layer security
<2s
Unlock on payment
8
Security layers
99%
SMS coverage Kenya
3
Product lines
Technology partners
Products
Three products.
One backend.

Clients choose the deployment mode that fits their hardware. All three connect to the same cloud, admin dashboard, and billing engine.

Core product
📱
PhoneLock Pro
Software-only PAYG for Android smartphones. Pre-installed before sale. No manufacturer partnership required. Works on Samsung, Tecno, Infinix, and Itel running Android 14–16.
  • Overlay + Device Owner locking
  • Internet unlock via FCM in under 2 seconds
  • SMS HMAC offline unlock fallback
  • 8-layer anti-bypass security
  • Composite hardware fingerprint binding
  • Factory reset protection
IoT hardware
⚡
SolarLock
GSM-enabled IoT control module for solar lights, torches, and home energy systems. A hardware relay physically cuts power on missed payment — impossible to bypass in software.
  • ESP32 + SIM800L GSM control unit
  • Hardware relay — physical power cutoff
  • SMS-triggered lock and unlock
  • Tamper-detection switch on enclosure
  • Energy usage tracking and reporting
  • Shared backend with PhoneLock Pro
B2B platform
🏢
FleetDesk
White-label admin dashboard and REST API for financial institutions, telcos, and device distributors managing PAYG fleets at scale. Deploy under your own brand.
  • Full white-label — your brand, your UI
  • Fleet view: lock status, heartbeat, payments
  • Manual lock/unlock with MFA gate
  • Bulk operations and CSV export
  • Agent portal for field sales teams
  • REST API for CRM/ERP integration
How it works
Payment to unlock
in under 2 seconds

Our two-path unlock system ensures customers can always access their device after paying — whether they have internet or not.

1
Customer pays via M-Pesa
Payment is made using any M-Pesa channel — STK push, Paybill, or USSD. No app required to initiate payment.
2
Backend verifies payment
Safaricom's Daraja webhook hits our Cloud Function within milliseconds. Payment amount, reference, and registered number are all validated.
3
Signed unlock command sent
An RS256-signed unlock command is pushed to the device via FCM. If the device is offline, an HMAC SMS code is sent to the registered number.
4
Device verifies and unlocks
The app verifies the signature or validates the SMS code locally against the device IMEI. If valid, the device unlocks immediately — no server round-trip needed.
Live unlock flow
💳
M-Pesa payment confirmed
Daraja webhook fires — 0ms
☁️
Cloud Function validates
Amount · reference · registered number — ~200ms
📡
FCM push dispatched
RS256-signed payload sent to device — ~400ms
✅
Device unlocked
Signature verified locally · lock removed — ~1.8s total
💬
SMS fallback (offline)
HMAC code · IMEI+ICCID bound · 2-hour window
<2s
average internet unlock time
Security
Built to be unbypassed.

Every security layer assumes the one below it has been compromised. We engineer for customers who have physical access, root tools, and technical knowledge.

🔑
Composite hardware binding
IMEI + CPU silicon serial + SIM ICCID + baseband version fused into one HMAC fingerprint. Changing any single value triggers an immediate alert and lock.
🛡️
Play Integrity attestation
Device attestation runs on every heartbeat. Rooted, emulated, or custom-ROM devices automatically fail and are hard-locked — no admin action required.
📜
Signed unlock commands
FCM unlock payloads are RS256-signed. The app verifies the server's public key before applying any unlock. Replayed or forged commands are silently rejected.
💬
HMAC offline codes
SMS unlock codes are device-specific, time-windowed, and ICCID-bound. A stolen code cannot be used on a different device or outside the 2-hour validity window.
🔬
Runtime threat detection
Detects Frida, Xposed, Magisk, ADB, emulators, debuggers, and clock rollback attacks in real time. Any detection triggers immediate hard lock and a backend alert.
🧱
Hardware Keystore
All tokens stored in Android Keystore with StrongBox/TEE hardware binding. Keys are physically unextractable — immune to EMMC dump and cold boot attacks.
Who we serve
Built for every player
in device financing

From SACCOs distributing 50 phones a month to telcos managing hundreds of thousands of devices — FleetDesk scales with you.

🏦
Microfinance institutions
Add device financing to your loan portfolio with automated enforcement and repayment tracking.
📡
Telcos & mobile operators
Run device subsidy programs like Lipa Mdogo Mdogo with enterprise-grade locking and M-Pesa integration.
🏪
Device distributors
Offer installment plans to your customers without building any infrastructure — we handle everything.
🤝
SACCOs & cooperatives
Enable member device financing with automatic enforcement tied directly to member accounts.
Technology
Built on infrastructure
Africa runs on

Every component chosen for reliability in low-connectivity, high-volume environments — from Nairobi's CBD to rural Kisumu.

📱
Native Kotlin — Android
Deep OS access for Accessibility Service, Device Owner, and hardware fingerprinting
🔥
Firebase + Cloud Functions
Firestore + FCM — real-time unlock pipeline, serverless billing logic
💬
Africa's Talking SMS
Dedicated shortcode, HMAC unlock codes, zero-internet fallback delivery
💚
M-Pesa Daraja API
Webhook-driven payment verification — triggers unlock in real time
⚡
ESP32 + SIM800L — IoT
GSM relay control unit for SolarLock — power cutoff, tamper detection, usage metering
📊
React — FleetDesk
Admin dashboard, agent portal, white-label ready, hosted on Firebase
Get started
Ready to deploy PAYG
financing in Kenya?

Tell us about your use case. We'll get back within one business day with a tailored proposal — no generic sales deck.

No commitment required · Response within 1 business day

✉️ nairobytes@gmail.com 📞 +254 794 570 888 🌐 nairobytes.co.ke