Custom Shopify checkout app with Square payments
A custom Shopify checkout app that integrates Square payments into the store's checkout flow.
I'm the Shopify and WordPress engineer at Inceptus Digital. I take on the work other developers avoid: custom Shopify apps, checkout and payment logic, broken plugin rescues, PHP upgrades, and stores that are slow or fragile. You can hire me directly through Upwork for $35/hr.
Sameer Hussain
Senior Shopify & WordPress Engineer
Inceptus Digital · Pakistan (UTC+5)
$35
per hour
13
Upwork jobs
30+
hrs / week
Custom apps, checkout and payment integrations (including Square), and Liquid theme work on Online Store 2.0.
Learn more →Custom plugins and themes, WooCommerce customization, and update-safe fixes for plugins someone edited directly.
Learn more →PHP 8 upgrades, query optimization, caching, Core Web Vitals, malware cleanup and security hardening.
Learn more →Product chatbots, n8n and Make automations, and bulk content tools using OpenAI or Claude APIs, running on the server.
Learn more →A custom Shopify checkout app that integrates Square payments into the store's checkout flow.
A premium Shopify redesign for a European fitness brand, built on clean Online Store 2.0 sections with no page builders.
Large multi-variant catalog and collection architecture for an Australian pet supply store.
Ongoing WordPress engineering and site management.
I look at your store or site before quoting, so the estimate is realistic and risks are flagged before anything changes.
All work happens on a staging copy or duplicate theme, tracked in Git, with a backup taken before any production change.
If a spec won't hold up technically, I'll tell you and propose a better option instead of building something fragile.
You get a short note with what changed, which files were touched, and how to undo it. No black boxes.
Contracts, billing and payment protection are handled by Upwork, and my Top Rated status, job history and client feedback are all public on my profile.
Start on UpworkYou fund each milestone up front and release payment only when you approve the work.
Set a weekly hour cap. Time is tracked in Upwork's Work Diary.
Upwork handles the contract, invoices and payment in your currency.
A read-only audit or a small paid task is the fastest way to see how I work.
A Top Rated Upwork developer's checklist for hiring: writing the job post, reading profiles, questions to ask, contract types, giving access safely and red flags.
Read the guide →
Set up an n8n workflow that adds every new WooCommerce order to Google Sheets in real time, keeps statuses updated, and fixes common webhook problems.
Read the guide →
Build a WordPress AI chatbot the secure way: a server-side REST endpoint with nonce checks, rate limits and the API key kept in wp-config.php, never in the browser.
Read the guide →
Square isn't a Shopify payment provider, but there are workable options: Square for POS with inventory sync, invoices for special orders, or a custom Square checkout app.
Read the guide →
A practical Shopify speed checklist: remove leftover app code, size images with image_url, fix LCP, tame third-party scripts and slow Liquid loops.
Read the guide →
Remove the leftover render or include tag behind Shopify's "Could not find asset" Liquid error (usually from an uninstalled app) and find every other leftover.
Read the guide →Through Upwork. Open his Upwork profile, click "Invite to job" (or "Hire"), and include your store or site URL and the problem. He replies within 4 hours.
$35/hour on Upwork, or a fixed price with milestones after a short read-only audit.
Shopify themes and custom apps, checkout and payment integrations (including Square), WordPress plugins and themes, WooCommerce customization, PHP 8 upgrades, malware cleanup, speed optimization and AI features like chatbots and n8n automations.
No. All work happens on a staging copy or duplicate theme, tracked in Git, with backups taken first. Every task ends with a handoff note.
Send me your store URL and the problem on Upwork. I reply within 4 hours and tell you how I'd approach it before you commit to anything.
Message me on Upwork