{"message":"This endpoint sells MyOTP.App credits to AI agents over HTTP 402 (Stripe Machine Payments), for pay-as-you-go accounts (an account on a monthly plan gets more credits by upgrading the plan). It takes a POST with your X-API-Key, not a GET.","method":"POST","url":"https://api.myotp.app/v1/topup","headers":{"X-API-Key":"<your key>","Content-Type":"application/json"},"body":{"credits":25},"flow":"First call answers 402 (403 for an account on a monthly plan) with a WWW-Authenticate: Payment challenge (USDC always; card once your email is confirmed). Pay it and retry with the credential; credits land once per payment.","pricing":{"credits":25,"amount_usd":"0.75","price_per_credit_usd":0.03,"min_credits":25,"max_credits":50000,"currency":"usd","card_daily_cap_usd":100},"quote":"https://api.myotp.app/v1/topup/quote?credits=100","cli":"npx @myotp/cli topup --credits 100","mcp":"npx @myotp/mcp (tools: get_topup_quote, top_up_credits) or https://mcp.myotp.app","link_cli":"npx @stripe/link-cli mpp pay https://api.myotp.app/v1/topup -X POST -d '{\"credits\":25}' -H \"x-api-key: <key>\" --context \"Buying MyOTP.App credits to send one-time passcodes over SMS, WhatsApp and Telegram for phone verification in my app.\"","no_key_yet":"POST https://api.myotp.app/v1/agent/register {\"email\":\"you@example.com\"}","docs":"https://myotp.app/developer-api/","human_checkout":"https://myotp.app/pricing/"}