Parousya
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Guides

How proximity payment actually works.

Reference guides on the method, the protocols, and the architecture. Each one answers its question in the first paragraph and earns the rest.

A robotaxi drives itself with cameras, radar, and lidar, but the curbside handshake is unsolved. How proximity identific
GuideHow do robotaxis work?A robotaxi drives itself with cameras, radar, and lidar, but the curbside handshake is unsolved. How proximity identification confirms the rider and the fare.July 8, 2026 · 10 min read
Ultra wideband, or UWB, times a radio pulse to place a device to roughly ten centimetres. How UWB ranging works and why
GuideWhat is ultra wideband?Ultra wideband, or UWB, times a radio pulse to place a device to roughly ten centimetres. How UWB ranging works and why that precision matters for payment.May 5, 2026 · 8 min read
Geofencing draws a virtual boundary and fires when a phone crosses it. How it works, why it locates coarsely, and how si
GuideWhat is geofencing?Geofencing draws a virtual boundary and fires when a phone crosses it. How it works, why it locates coarsely, and how signal based proximity differs.January 19, 2026 · 8 min read
The proximity method is Parousya's patented way to identify the right provider nearby and pay without the devices ever c
GuideThe proximity methodThe proximity method is Parousya's patented way to identify the right provider nearby and pay without the devices ever connecting directly. How it works.January 30, 2025 · 11 min read
NFC mobile payment pays with a phone over NFC and EMV, storing a token instead of your card number. How the tap works an
GuideWhat is NFC mobile payment?NFC mobile payment pays with a phone over NFC and EMV, storing a token instead of your card number. How the tap works and the rails behind it.October 4, 2024 · 8 min read
A QR code payment encodes account data in a square a camera reads. How QR payments clear, where they strain, and how rad
GuideHow do QR code payments work?A QR code payment encodes account data in a square a camera reads. How QR payments clear, where they strain, and how radio based proximity compares.June 27, 2024 · 7 min read
NFC stands for Near Field Communication, a short range radio at 13.56 MHz. How it works, what it does on your phone, and
GuideWhat is NFC?NFC stands for Near Field Communication, a short range radio at 13.56 MHz. How it works, what it does on your phone, and how proximity payment uses it.October 19, 2023 · 9 min read
Contactless payment means holding a card or phone near a reader instead of swiping. How the tap clears over NFC and EMV,
GuideWhat is contactless payment?Contactless payment means holding a card or phone near a reader instead of swiping. How the tap clears over NFC and EMV, and what comes after it.March 23, 2023 · 8 min read
Tap to pay works over NFC and the EMV contactless standard. How a single tap moves an encrypted token, and where proximi
GuideHow does tap to pay work?Tap to pay works over NFC and the EMV contactless standard. How a single tap moves an encrypted token, and where proximity payment goes further.November 1, 2022 · 8 min read
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Licensing

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We license the Parousya method to companies building where proximity and payment intersect. If you can see an application, we would like to hear from you.

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