Senior API Developer Needed – Custom Private App Integration (WHOP → Funnelish)
We are a fast-scaling ecommerce brand looking for a highly experienced API developer to build a custom private app that connects our payment gateway (WHOP) with Funnelish.
Funnelish does not have a native integration with WHOP.
We need someone who has handled complex payment gateway integrations before — not someone experimenting. This is not a junior project. We’re looking for a proven expert who has solved similar integrations successfully.
We need a private app or middleware solution that:
• Connects WOP payment processing to Funnelish
• Properly passes order data to Funnelish
• Correctly tracks initial purchases
• Correctly tracks post-purchase upsells
• Ensures tracking consistency (order value, customer data, transaction status)
• Handles webhook logic reliably
• Prevents duplicate or broken orders
• Maintains accurate attribution and tracking inside Funnelish
This must work cleanly for:
• Main product checkout
• One-click upsells
• Post-purchase flows
Tracking accuracy is critical.
⸻
Required Experience
You must have:
• Strong experience building private apps
• Advanced experience with APIs and webhooks
• Experience integrating payment gateways into third-party platforms
• Experience working with ecommerce funnels
• Deep understanding of order lifecycle, payment states, and tracking logic
⸻
This Is NOT for You If:
• You are “learning as you go”
• You are unsure whether this can be done
• You have never handled custom payment integrations
We are looking for someone confident and experienced.
⸻
To filter serious and qualified applicants, you MUST answer these questions clearly at the top of your proposal:
1. Have you ever done this exact type of integration (custom payment gateway → funnel builder)? If yes, explain briefly.
2. Have you done a similar integration involving custom APIs and payment webhooks? If yes, describe it.
3. Are you 100% confident you can complete this task successfully? Explain why.
If you do not answer these 3 questions clearly, your application will not be considered.
Apply tot his job
Apply To this Job
Funnelish does not have a native integration with WHOP.
We need someone who has handled complex payment gateway integrations before — not someone experimenting. This is not a junior project. We’re looking for a proven expert who has solved similar integrations successfully.
We need a private app or middleware solution that:
• Connects WOP payment processing to Funnelish
• Properly passes order data to Funnelish
• Correctly tracks initial purchases
• Correctly tracks post-purchase upsells
• Ensures tracking consistency (order value, customer data, transaction status)
• Handles webhook logic reliably
• Prevents duplicate or broken orders
• Maintains accurate attribution and tracking inside Funnelish
This must work cleanly for:
• Main product checkout
• One-click upsells
• Post-purchase flows
Tracking accuracy is critical.
⸻
Required Experience
You must have:
• Strong experience building private apps
• Advanced experience with APIs and webhooks
• Experience integrating payment gateways into third-party platforms
• Experience working with ecommerce funnels
• Deep understanding of order lifecycle, payment states, and tracking logic
⸻
This Is NOT for You If:
• You are “learning as you go”
• You are unsure whether this can be done
• You have never handled custom payment integrations
We are looking for someone confident and experienced.
⸻
To filter serious and qualified applicants, you MUST answer these questions clearly at the top of your proposal:
1. Have you ever done this exact type of integration (custom payment gateway → funnel builder)? If yes, explain briefly.
2. Have you done a similar integration involving custom APIs and payment webhooks? If yes, describe it.
3. Are you 100% confident you can complete this task successfully? Explain why.
If you do not answer these 3 questions clearly, your application will not be considered.
Apply tot his job
Apply To this Job