Show HN: Unified Payment Sandbox – A UAT Env for Stripe/Razorpay Integrations https://ift.tt/YdiFrz5

Show HN: Unified Payment Sandbox – A UAT Env for Stripe/Razorpay Integrations Hey HN! I'm exploring an idea for a developer-focused SaaS: A unified UAT environment for payment gateways — essentially a sandbox simulator that lets developers integrate payments without creating multiple sandbox accounts or dealing with inconsistent/mock behaviors across gateways. The Problem If you’ve ever integrated payments, you know: Stripe has excellent test tooling Razorpay is decent Paytm/PayU/etc vary a lot Many banks don’t have predictable UAT behavior Webhooks arrive differently, some delayed, some flaky Testing disputes/refunds/settlements is nearly impossible For dev teams building complex flows, they end up writing internal mocks, maintaining them, and still missing edge cases. The Idea (SaaS) A unified Payment Sandbox Simulator that: Mock APIs for multiple gateways Stripe Razorpay Paytm PayU Cashfree Worldline Visa/Mastercard tokenization mock UPI PSP simulators Simulate real-world scenarios Captures Refunds Partial refunds Chargebacks Disputes Settlement delays Failed payouts KYC verification Randomized webhook delays/skips Network downtime simulation 3-D Secure / OTP mock pages UPI timeouts / pending states Hosted dashboards View mock transactions Trigger lifecycle events (manually or timed) Trigger webhooks again Create custom gateway profiles Define “rules” to simulate: failure %, latency, webhook disorder, retries For engineering teams Private UAT environment in one URL No more creating 10 sandbox accounts CI-friendly “headless payment” flows Add Mock PG in local → swap to real PG in staging Automatic contract testing Pricing thought Free Tier → 100 test transactions/mo $29/mo → small teams $99/mo → startups $499/mo → enterprise / white-label Ask to HN Would you use this? What’s missing? Would payments teams trust a 3rd-party simulator? Which gateways or scenarios matter most? Happy to answer questions November 14, 2025 at 11:02PM