How I Connected x402 Payments to a Real API on Algorand
Over the past few weeks I decided to enter the x402 challenge and see if I could connect machine-to-machine payments to a real API.
The goal was simple:
Build an API that can provide useful information to applications, dashboards, and AI agents while allowing usage-based payments through x402.
The API
The project is called KepAIx. KepAIx is an educational market intelligence platform that combines local AI processing, market regime analysis, and machine-readable API services.
KepAIx generates educational market intelligence snapshots from what I call the Main Brain.
The API returns a lightweight machine-readable market regime assessment including:
- Market mode
- Market state
- Confidence score
- Risk score
- Educational summary
The idea is not to provide trading advice.
The goal is to provide machine-consumable educational market intelligence.
Why x402 Interested Me
Most APIs still rely on:
- Monthly subscriptions
- API keys
- User accounts
- Billing systems
x402 introduces a different possibility.
Instead of requiring a subscription, an application can simply pay for the request itself.
That opens interesting possibilities for:
- AI agents
- Automated workflows
- Research tools
- Dashboards
- Machine-to-machine services
The Hardest Part
The hardest part wasn't building the API.
The hardest part was understanding the complete payment flow.
I wanted to make sure the process was doing real verification and real settlement rather than simply simulating a payment.
Getting a full end-to-end flow working required:
- Building the endpoint
- Understanding facilitator verification
- Testing payment handling
- Confirming settlement
- Validating successful responses
Once the first successful paid request completed, the architecture became much easier to understand.
What Surprised Me
The biggest surprise was how natural usage-based pricing feels for machine services.
Humans are accustomed to subscriptions.
Machines don't necessarily need subscriptions.
A service priced per request can be easier for software to consume than forcing account creation and recurring billing.
Current Endpoint Configuration
Network: Algorand Mainnet
Asset: USDC ASA 31566704
Price: 0.01 USDC per request
Protocol: x402
Public Documentation
Documentation:
https://kepaix.com/api-docs.php
GitHub:
https://github.com/keppy66/kepaix-x402-api
Lessons Learned
My biggest takeaway is that machine payments feel much more practical once you actually connect them to a working service.
Reading about x402 is one thing.
Watching a real payment unlock a real API response is something entirely different.
I'm interested in hearing how other developers are approaching x402, usage-based pricing, and machine-to-machine services.
