Payment Integration in a Website: Build It Around Webhooks, Idempotency, and a Ledger
Payment integration in a website fails in the webhook handler, not the checkout form. Seven common assumptions, where each breaks, and the fix.
Custom web application development by EltexSoft. SaaS, marketplaces, B2B portals. MyFlyRight (€100M+), Nautical Commerce. $50-99/hr.
EltexSoft is a custom web application development company with senior full-stack engineers available at $50-99/hr. We build SaaS platforms, two-sided marketplaces, B2B portals, and enterprise web applications. Clients include MyFlyRight (€100M+ recovered, 10-year partnership), HeyTutor (9-year EdTech marketplace), Nautical Commerce ($30M Series A), Greek House (Inc. 5000, acquired 2024), and Ripe (acquired by Hungry).
What we ship
Multi-tenant applications with subscription billing, role-based access, admin dashboards, and API integrations. RiseMD powers healthcare marketing analytics for dental practices and DSOs.
Matching algorithms, search and discovery, payments with Stripe Connect, messaging, review systems. Built HeyTutor (tutoring), Nautical Commerce (ecommerce), Snapwire (photography), and Ripe (catering). Four marketplace exits or acquisitions.
Internal tools, client dashboards, operations consoles, reporting interfaces. The applications that run a business behind the scenes. Three interconnected dashboards for Ripe's catering operations (customer, kitchen, operations).
CodeIgniter, jQuery, AngularJS to modern Laravel, React, Vue, Django. Greek House is the reference: we upgraded its Laravel codebase several major versions forward on an Inc. 5000 ecommerce platform.
Backend (Laravel, Django, Node.js) paired with frontend (React, Vue, Angular). API design, database architecture, authentication, deployment. One team builds the whole application.
Caching (Redis, Varnish), database optimization, CDN configuration, load testing. Nautical Commerce processes 200K+ monthly transactions. HeyTutor serves 10,000+ concurrent users during peak hours.
Nautical Commerce. $30M Series A. Acquired by Traide. Greek House. Inc. 5000 multiple years. Acquired 2024. Ripe. Catering marketplace. Acquired by Hungry. Snapwire. Photography marketplace for Dell and Starbucks. Acquired by StudioNow. HeyTutor. 9 years continuous. Forbes 30 Under 30 founders. LAUSD contract. MyFlyRight. 10 years continuous. €100M+ recovered for air passengers.
Every one of these is a web application we built or rebuilt from scratch. Every one passed technical due diligence from acquirers, investors, or government procurement. That is the standard we build to.
EltexSoft is a custom web application development company. 35-50 senior engineers. Headquartered in Los Angeles, with offices in New York, Lisbon, and Kyiv. Engineering team in Ukraine. Founded in 2015.
Multi-tenant web applications with subscription billing (Stripe), role-based access control, admin dashboards, API integrations, and white-label capabilities.
RiseMD is a SaaS analytics platform for dental practices and DSOs. Patient attribution from first ad click to revenue. EHR integration. AI-powered call grading. Multi-location dashboards for organizations managing 5 to 300+ practices. 20X ROI.
The engineering pattern we know best. Over the past 11 years, we have built more marketplaces than any other application type.
HeyTutor: Student-tutor matching with 100+ metric algorithm. 9 years. Nautical Commerce: Marketplace operator PaaS. 200K+ monthly transactions. Snapwire: Brand-photographer matching for Fortune 500s. Millions of images. Ripe: B2B catering subscriptions. 1,000+ weekly orders. Three dashboards.
Each marketplace has its own matching logic, payment splitting model, and operational complexity. The common engineering: Stripe Connect for payment splits, real-time messaging, search with Elasticsearch, review and rating systems, and admin dashboards that give operators visibility into both sides.
The applications nobody sees but every business needs. Client dashboards. Operations consoles. Reporting interfaces. Approval workflows. Inventory management. CRM integrations.
Ripe had three interconnected dashboards: customer ordering, kitchen operations, and delivery logistics. All operating on the same data. An order placed at 9 AM appeared on the kitchen schedule by 9:01.
Codebases age. Frameworks reach end-of-life. The team that built V1 leaves. The new code nobody wants to touch becomes the code everybody depends on.
We migrate. We upgraded Greek House’s Laravel codebase several major versions forward. We have also migrated CodeIgniter, Kohana, CakePHP, Zend, jQuery, and AngularJS applications to modern stacks.
Backend: Laravel (primary), Django, PHP, Python, Node.js. Frontend: React, Vue.js, Next.js, Nuxt.js. Database: PostgreSQL (default), MySQL, MongoDB, Redis, Elasticsearch. Infrastructure: AWS, GCP, Hetzner. Docker. GitHub Actions CI/CD. Payments: Stripe, Stripe Connect, PayPal, ACH.
Senior full-stack developer (dedicated): $50-99/hr.
Web application MVP: $40K-$100K, 3-6 months. Two-sided marketplace: $80K-$200K, 5-10 months. SaaS platform: $60K-$150K, 4-8 months. Legacy migration: $50K-$150K, 4-8 months. Enterprise web application: $100K-$300K, 6-12 months.
EltexSoft is a boutique custom web application development company. 35-50 senior engineers. Headquartered in Los Angeles, with offices in New York, Lisbon, and Kyiv. Engineering team in Ukraine. Founded in 2015.
Web application clients: HeyTutor (9yr), MyFlyRight (10yr, €100M+), Nautical Commerce ($30M), Greek House (acquired), Ripe (acquired), Snapwire (acquired). We also build mobile apps, AI products, and provide CTO as a service.
5.0 Clutch rating across 30+ verified reviews. 200+ five-star Upwork reviews. Top Rated Plus and Expert-Vetted. Average client engagement: 3+ years.
Field notes
Payment integration in a website fails in the webhook handler, not the checkout form. Seven common assumptions, where each breaks, and the fix.
FAQ
One business day reply. From an engineer, not a sales rep.