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I will fix, integrate, or rebuild square payment gateway and square pos
Karoly Nyisztor
About this gig
Are you experiencing issues with your Square p ayment gateway, broken checkout flows, or a messy Square POS item library? Most setup errors lead to dropped conversions, miscalculated sales reporting, or failed transactions.
I specialize in integrating, auditing, fixing, and restructuring Square peyment solutions across e-commerce platforms, custom web apps, and Point of Sale (POS) systems. Whether you need a fresh integration or an urgent fix for an existing setup, I will ensure your checkout is secure, compliant, and seamless.
What I Offer:
- Square Payment Gateway Integration (WooCommerce, WordPress, Webflow, Wix, Squarespace, Custom Apps)
- Square POS Library Cleanup & Restructuring (Categories, Modifiers, SKUs, Variations)
- Bug Fixing: Resolving failed checkouts, webhook timeouts, API errors, and currency mismatches
- Digital Wallets & In-Person Options (Apple Pay, Google Pay, Tap-to-Pay)
- Booking & Subscription Integration (Square Subscriptions, Appointment booking slots)
- Multi-Location & Sync Setup (Syncing online store stock with in-person POS inventory)
Let's make sure your store processes payments smoothly. Please send me a message with your site or POS details
Get to know Karoly Nyisztor
Karoly Nyisztor
Website, Web App Developer, AI Solutions
- FromColombia
- Member sinceMar 2025
- Avg. response time5 hours
Languages
English, Spanish
I’m Karoly Nyisztor, a website and web app developer specializing in modern websites, custom web applications, and AI-powered solutions. I help businesses turn ideas into functional, responsive, and user-friendly digital experiences. Whether you need a business website, a custom web app, or AI integrations to streamline your workflow, I focus on quality, clear communication, and solutions tailored to your goals. Let’s bring your ideas to life!
My Portfolio
FAQ
Why Work With Me?
- Clean Code & Scalable Architecture - Deep understanding of payment APIs, webhooks, and sandbox testing - End-to-end testing to ensure 100% successful transaction processing - Standard Git deployment & clear post-setup handover documentation
Can you fix an existing Square peyment issue without rebuilding my entire setup?
Yes! If your gateway is throwing errors, failing at checkout, or not syncing properly, I can audit your API settings, webhook triggers, and code configurations to fix the specific issue without disturbing your existing workflow.
Which website platforms do you support for Square integration?
I integrate Square across all major platforms including WordPress/WooCommerce, Webflow, Squarespace, Wix, Shopify, as well as custom-built Next.js, React, or PHP web applications via direct API integrations.
Can you organize or rebuild my Square POS item library and categories?
I can clean up duplicate items, structure modifier sets, create standardized product categories, assign SKUs, and ensure clean sales reporting across all your locations.
Will my live store experience any downtime during the integration or fix?
No. All configurations and fixes are thoroughly tested in a staging/sandbox environment or isolated team access login prior to deploying to your live environment to ensure continuous operation
What do you need to get started?
Depending on the job, I will need temporary access to your Square Dashboard (via Square’s team management permissions—never your main owner credentials), website admin access, or API keys (Application ID and Access Token).
