You will get a secure Stripe backend with verified webhooks and replay protection
Project details
I will build or repair a narrowly scoped Stripe payment backend for a web application.
Depending on the tier, the work can include hosted checkout, signature-verified webhooks, an idempotent event ledger, subscription state, entitlements, bounded retries, reconciliation, automated tests, and deployment documentation.
The Standard tier is the best fit for a new checkout and webhook path. Advanced is intended for recurring subscriptions and durable application access state.
Included:
• typed source code
• sandbox fixtures
• focused acceptance tests
• environment-variable template
• setup and verification documentation
Not included unless specifically added:
• storefront redesign
• merchant-account approval
• tax or accounting configuration
• migration of an unrelated billing system
• storage or processing of raw card data
I use sandbox credentials during development. Production secrets should only be configured in the approved deployment environment.
Depending on the tier, the work can include hosted checkout, signature-verified webhooks, an idempotent event ledger, subscription state, entitlements, bounded retries, reconciliation, automated tests, and deployment documentation.
The Standard tier is the best fit for a new checkout and webhook path. Advanced is intended for recurring subscriptions and durable application access state.
Included:
• typed source code
• sandbox fixtures
• focused acceptance tests
• environment-variable template
• setup and verification documentation
Not included unless specifically added:
• storefront redesign
• merchant-account approval
• tax or accounting configuration
• migration of an unrelated billing system
• storage or processing of raw card data
I use sandbox credentials during development. Production secrets should only be configured in the approved deployment environment.
Web Programming Project
API Development, API IntegrationProgramming Languages
JavaScript, TypeScriptCoding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$149
|
Standard
$799
|
Advanced
$1,999
|
|---|---|---|---|
| Delivery Time | 3 days | 7 days | 14 days |
Number of Revisions | 1 | 2 | 2 |
Source Code |
Optional add-ons
You can add these on the next page.
Fast Delivery
+$100 - $500
Additional Revision
+$100
Additional webhook event
(+ 1 Day)
+$125
Additional API endpoint
(+ 2 Days)
+$175
Production deployment
(+ 2 Days)
+$250Frequently asked questions
About Kareem
Custom Software Developer | Apps, Automation & AI-Enabled Tools
Lisle, United States - 3:19 pm local time
I bring more than eight years of IT and systems experience from university and financial-enterprise environments, including supporting technology used by an organization with more than 1,500 users. I also have a computer science degree, three published apps on the Apple App Store, and a growing portfolio of independent software projects.
I build custom applications, workflow automations, internal tools, API integrations, web scrapers and crawlers, data systems, websites, and specialized utilities. I am equally open to complete app, game, and web-development projects—not only automation work.
My strongest fit is a project where a business has too much repetitive work, too many disconnected steps, a process that has outgrown spreadsheets, or an idea that needs to become a practical, usable application.
My enterprise background has made me especially careful about privacy, documentation, operational reliability, and dependable handoff. I also make extensive use of modern AI-assisted development tools, including tools I have built myself. Where useful, I design software with MCP or other agent-ready interfaces so AI systems can operate it, connect it with other applications, or incorporate it into a larger workflow.
Whether the project is a focused automation, an internal business system, a customer-facing application, or a more experimental software product, my goal is to understand the real problem and build something that saves time, works reliably, and remains useful after delivery.
Steps for completing your project
After purchasing the project, send requirements so Kareem can start the project.
Delivery time starts when Kareem receives requirements from you.
Kareem works on your project following the steps below.
Revisions may occur after the delivery date.
Define the payment state contract
I review the accepted scope, existing code, payment events, products or plans, and the application states each verified event should create.
Implement the trusted payment boundary
I implement checkout, signature verification, event deduplication, state persistence, validation, and scoped failure handling.