Paxos
Paxos Technical Briefing
Published November 17, 2020
Supported by The Kauffman Foundation and Modern Treasury
Overview
Zach Portler, product lead at Paxos, introduces Paxos as the regulated-custodian gateway between physical and digital assets, built for the multi-decade migration of $600T of assets from closed ledgers to public blockchains. Paxos is unusual in offering regulated custody and tokenization across four asset classes — crypto, cash, commodities, and securities — including USD-backed stablecoins (wire in, Paxos mints 1:1-redeemable tokens) and Pax Gold (PAXG), where tokenized gold balances on Ethereum are backed by physical gold in an unallocated account. This earlier briefing zooms in on the PayPal crypto partnership Paxos powers: the Paxos admin portal's signing ceremony for moving assets between banks and blockchains, and the four Paxos API endpoints PayPal uses under the hood (list-historical-prices for the chart, list-quotes to price a buy, create-quote-executions for the actual order, tickers for real-time holdings).
0:00 Introduction to Paxos — regulated custodian gateway
Zach Portler, product lead at Paxos, introduces Paxos — a regulated custodian acting as the gateway between physical and digital assets. The thesis: over the next two decades, a significant portion of the world's $600T of assets will migrate from closed ledgers to public blockchains.
1:00 Multi-asset custodian — crypto, cash, commodities, securities
Paxos is unusual in that it offers regulated custody and tokenization across four asset classes — crypto, cash, commodities, securities. The goal is to be a one-stop shop for any digital asset a customer wants to hold, tokenize, or mobilize.
1:30 USD stablecoin mint and redeem flow
Example flow: wire $1M to Paxos, Paxos mints USD-backed tokens on Ethereum and transfers them to your wallet. Anyone holding those tokens can return them to Paxos for 1:1 USD redemption — backed by the fact Paxos is regulated like a bank.
2:30 PayPal crypto partnership — the demo
Paxos powers PayPal's crypto offering, which rolled out to US users in mid-October 2021 across web and mobile. The demo walks through buying $5 of Bitcoin directly in the PayPal app.
4:00 API walkthrough — historical prices endpoint
The price chart in PayPal comes from /list-historical-prices with a BTC-USD pair and a requested data-point count — a time series ready for UI visualization.
5:00 Quotes endpoint — buy/sell price with expiration
When a user requests a buy, PayPal hits Paxos's /list-quotes endpoint for BTC-USD. Paxos returns a quote with buy side, sell side, price, base and quote assets, and an expiration time.
5:30 Create quote execution — POST to buy
Clicking Buy fires /create-quote-executions — the POST that actually orders the trade. The body references the quote ID and the USD amount; Paxos returns a report with the buy price, quantity, and USD debited.
6:30 Tickers endpoint for real-time holdings
Returning to the PayPal holdings screen, PayPal calls Paxos's /tickers endpoint for best bid/ask to construct a real-time asset price — the visible UX, driven by a simple API.
7:00 Paxos signing ceremony — treasury operations
A look inside the Paxos admin portal: the signing ceremony page operations uses multiple times a day to move assets between banks and blockchains. The network graph visualizes Paxos's holdings per chain.
7:30 PAXG (Pax Gold) — tokenized commodity
Walk-through of PAXG, Paxos's tokenized gold: on-chain crypto addresses hold tokenized gold balances, while an unallocated gold account tracks the physical bars backing every token 1:1.
Presented by Zach Kwartler — Paxos · website
Topics: Stablecoins, Crypto Infrastructure, Compliance & Regulation
