How a 21 Year Old Builds Shopify Apps With AI Agents
Liquid Weekly Podcast: Shopify Developers Talking Shopify DevelopmentShow Notes
Taylor is in India for Shop Quest, so Karl flies solo with Charles Swayne, owner and app developer at JadePuma Apps and the person behind Datify. Charles is 21, learned Python in sixth grade, and now runs a multi-agent development workflow that researches, plans, audits the plan, executes, and tests itself before he ever looks at the code.
We get into what that workflow actually looks like, which models he reaches for at each step and why, how he runs his own evals, and whether any of us should still be reading the PR. Plus Datify, structuring product data for agentic commerce, and what it was like when Mantle shut down.
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SPONSOR
Promo Party Pro is a free gift with purchase app Karl helped build with the team at Ethercycle. Set a spend threshold, show shoppers how close they are to earning a gift, and let the app handle the rest. Discount Functions under the hood, one app embed, no theme surgery, and campaigns auto-pause when the gift sells out.
Agencies: one of your clients gets a full year free. Not a trial, a year. https://promoparty.app/agency
Promo Party Pro - https://promoparty.app/ On the Shopify App Store - https://apps.shopify.com/promo-party-fgwp
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FIND CHARLES ONLINE
LinkedIn - https://www.linkedin.com/in/charles-swayne/ Datify on the Shopify App Store - https://apps.shopify.com/datify JadePuma Apps on the Shopify App Store - https://apps.shopify.com/partners/jadepuma-apps JadePuma - https://jadepuma.com/ BBQ on Ingraham, his neighborhood potluck - https://bbq-on-ingraham.onrender.com/
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TIMESTAMPS
Timestamps generated by AI show notes. These may shift slightly after final edit.
00:00 – Cold open: the boot disk that broke Dad's computer 00:35 – Taylor is in India, so Karl is on his own 01:17 – Meeting at the water cooler, which was really the Diet Coke 02:50 – Python in sixth grade and a choose your own adventure ham sandwich 03:37 – The internship with Scott Austin that turned into a career 06:29 – The Rutgers full stack certificate, before Claude existed 07:55 – How JadePuma Apps turns one client's problem into an app 08:47 – Admin extensions and printing jukebox strips from an order 09:45 – Tech stack, Heroku, Vercel, and the fear of picking the next Heroku 11:48 – When Mantle shut down 14:56 – Sponsor: Promo Party Pro 16:10 – What Datify does, and the merchant with 700,000 products 19:05 – Seven apps, two Built for Shopify, and figuring out pricing 20:59 – The agentic workflow: research, plan, audit, execute, test, review 22:00 – The plan reviewer skill, and why the plan matters more than the code 24:25 – Subagent phases and picking a model for each one 27:16 – Running your own evals: same prompt, two models, fifty times 28:30 – Screenshots, phone notifications, and automated test reports 29:57 – Hallucinations, scheming, and the Haiku that switched to Russian 33:41 – Do you read the PR? Every AI feature ships with a security bug 36:23 – When the review loop never ends and you wonder if you should have done it yourself 41:08 – Missing the grunt work, and grieving it together 43:09 – From DOS 5 to agents, what we gained and what we lost 44:44 – The SimCity theory of programming with agents 47:00 – Dev Changelog 49:15 – Picks of the Week
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PICKS OF THE WEEK
Karl: When Life Gives You Pears by Jeannie Gaffigan - https://www.amazon.com/dp/1538751046 – Her account of having a brain tumor removed, her family, and her faith. Not Karl's usual read, and it stuck with him.
Charles: Keyviz - https://keyviz.org/ – A widget that shows your last ten keystrokes, so when you fat-finger a shortcut you can see what you just did and undo it.
More from Liquid Weekly Podcast: Shopify Developers Talking Shopify Development
Georgi Petrov, CEO and co-founder of Uxify, joins Karl and Taylor to talk about the half of web performance nobody optimizes for: the shopper's device. After building SMS Bump (acquired by Yotpo), ConsentMo, and NitroPack (acquired by WP Engine), Georgi is now tackling device-specific friction, the laggy buttons, layout shifts, and interaction delays that vary wildly from one phone to the next. We get into how Uxify profiles a visitor's capability without touching your code, the specialized agents that fix problems on the fly, the ClickHouse-powered data layer behind it all, and how to think about performance heading into BFCM. Plus the Dev Changelog and Picks of the Week. Sponsor The Support Heroes: https://www.thesupportheroes.com/ Subscribe to Liquid Weekly Don't miss out on expert insights and tips. Subscribe to Liquid Weekly for more content like this: https://liquidweekly.com/ Find Georgi Online Uxify: https://uxify.com/integrations/shopify/ LinkedIn: https://www.linkedin.com/in/georgipetrov/ Timestamps (00:00) Open (00:29) Intros (02:11) Meet Georgi Petrov of Uxify (02:54) Origin story: hardware hacking to his first software (06:03) Finding Shopify: SMS Bump, ConsentMo, and NitroPack (12:23) Making fast decisions and failing cheaply (15:32) Why Uxify: performance is half website, half device (20:11) How it works: profiling devices and adapting on the fly (26:17) Sitting alongside your theme without touching your code (28:26) Real user monitoring and specialized agents (37:47) The tech stack: ClickHouse and heavy browser testing (41:57) Shopify cart variations and a clever checkout fallback (46:24) Prepping for BFCM and who Uxify is for (51:14) Dev Changelog (58:22) Picks of the Week Dev Changelog [action required] Variants now support multiple barcodes: https://shopify.dev/changelog/product-variant-barcode-is-being-replaced-by-barcodes Create and delete dev stores in Shopify CLI: https://shopify.dev/changelog/create-and-delete-dev-stores-in-shopify-cli [action required] Discounts Allocator Function API developer preview has ended: https://shopify.dev/changelog/discounts-allocator-function-api-developer-preview-has-ended Delivery options in Shopify Functions input now expose their metafields: https://shopify.dev/changelog/delivery-options-in-shopify-functions-input-now-expose-their-metafields Prepare your app for the Shopify admin's new look: https://shopify.dev/changelog/prepare-your-app-for-the-shopify-admins-new-look [action required] Updates to Events payloads and subscription configuration: https://shopify.dev/changelog/updates-to-events-payloads-and-subscription-configuration New Pricing audit trail for contextual product variant prices: https://shopify.dev/changelog/pricing-audit-trail-for-contextual-product-variant-prices [breaking api change] [action required] Removed session.currentSession.staffMemberId from POS UI Extensions (2026-10): https://shopify.dev/changelog/removed-session-currentsession-staffmemberid-from-pos-ui-extensions-2026-10 Request a bundle size exception for existing UI extensions: https://shopify.dev/changelog/request-a-bundle-size-exception-for-existing-ui-extensions Picks of the Week Karl: Keto Oreo-style sandwich cookies (about 50 calories each), part of his ongoing tour through packaged keto snacks: https://www.choczero.com/products/keto-sandwich-cookies Georgi: Calisthenics between AI prompts. Knocking out push-ups and squats while waiting on an agent, which he says burns the time well and sharpens his focus when he comes back. Taylor: Ted Lasso, season 4 on Apple TV+. Still, in his words, one of the most wholesome shows around: https://www.imdb.com/title/tt10986410/
Prakhar Shrivastava of FoxSell joins Karl and Taylor to talk about Shop Quest, the Shopify community event he and his team run in Bengaluru, and to prep Taylor for his first trip to India.
In this episode of the Liquid Weekly Podcast, hosts Karl Meisterheim and Taylor Page are joined by Alexander Hupfer, founder of Fusion Metrics and a solo Shopify app developer.
Episode 073 – I Hid Swag and I'd Do It Again! - Recapping our DotDev Adventure
Recorded live at Shopify's DotDev, this special is two sessions in one. First, Ben Sehl walks Karl and Taylor through the future of Liquid: why the language is being reshaped for the agentic era, the new Partials tag that replaces the section rendering API, arrays and Booleans finally landing, agents.md and design.md guidance, and the Tailwind partnership.