Emily Kurtz is Head of Product at Public, the brokerage for people who take investing seriously, and she is responsible for all of its trading. That includes Public's newly launched trading API. She joined us with Public's AI lead, Jake Trefethen, in Episode 8 (August 15, 2025), where Jordan showed a trading bot he built on that API and Emily told him what she would change.
At 02:37 Emily laid out the product: stocks, bonds, treasuries, options and crypto, plus yield products such as a bond account and a treasury account. Customers can open brokerage accounts, IRAs and Roth IRAs.
Over the past year, she said at 21:45, Public built out that foundation. It was the first to offer fractional bonds, added a treasury ladder, and expanded the active-trader side with options and margin. The next step is using AI to deliver things she believes the market has not seen yet, such as the generated assets Jake described, portfolios across asset classes, and support for other account types like trusts.
Emily framed the API at 03:03 as another front end. It is for people who do not want Public's UI but want execution and programmatic access to their account. It launched with the core capabilities, trading equities and options, over a REST interface.
The roadmap she gave covers trading crypto and bonds, money movement, WebSockets, MCP and Python SDKs. Near the end of the episode she tied the API back to MCP and the value of letting LLMs connect to account data in a clear way.
Obviously, like, making me vibe code something that we're gonna put into production that directly impacts, their withdrawals, funds, whatever it may be, is it's pretty risky.
— Emily Kurtz, Episode 8
How you work cross functionally, how you manage bunch of different stakeholders, how you prioritize, how you bring in the voice of the customer and communicate with them, how you make a team more efficient and sort of push them to be the best product velocity they can, all of those things you're not gonna get via coding.
— Emily Kurtz, Episode 8
Jordan built the Public API trading bot in Replit in about three to six hours. Every 30 seconds it sends the IBIT price, his holdings, trade history, buying power and risk settings to ChatGPT, which decides whether to buy or sell through Public's API. It has stop-loss, max position size, aggressiveness and cash-float settings, plus a "disco mode" theme.
At 15:02 Emily asked what he would add with more time. His answer: a Supabase back end with better cron jobs, and a market-hours API. When Sam asked for the result at 16:37, Emily read it off the account: Jordan started with $300 and was at $299 after about ten to twelve trades. She was also the first to say it out loud: this is not investment advice. For more on brokerages and trading tools from the show, see AI in finance.
Emily Kurtz is Head of Product at Public, where she is responsible for all of the brokerage's trading, including its API. She joined Built This Week in Episode 8 with Public's AI lead, Jake Trefethen.
Emily describes it as another front end for people who want execution and programmatic access to their Public account without using the app. It launched as a REST interface for trading equities and options.
Emily said Public is adding crypto and bond trading and money movement, plus WebSockets, MCP support and Python SDKs.
Jordan built one in Replit in three to six hours, with ChatGPT deciding buy or sell on IBIT and Polygon supplying prices. It roughly broke even over about a dozen trades, and everyone on the episode stressed it is not investment advice.
