Urgent Pesapal Gateway Integration

I have an existing website that is already live and taking traffic, but the checkout flow is still missing a working payment solution. I need Pesapal (https://www.pesapal.com) fully integrated, end-to-end, and I am on a very tight timeline: everything has to be up and running within the next 5 hours of project start.

You will receive:
• API keys and merchant credentials
• Server and code-base access (SSH / cPanel or Git, depending on your workflow)
• Test data so we can run dummy payments before switching to live mode

What I expect back:
• Cleanly written integration code that slots into my existing stack without breaking current functionality
• A brief README or comment block explaining where you touched the code and how to update keys in future
• One successful live transaction (value equivalent to $1) demonstrated on a screen-share or short Loom video
• Error handling: user-friendly messages for failed or cancelled payments

I handle deployment; you just push the changes (or hand over the files) and walk me through any environment variables I need to set. If you have already worked with Pesapal or similar REST/JSON payment APIs, you should be able to knock this out quickly. Please only take the job if you can focus on it immediately—the 5-hour window is hard.