Introduction
What SendMock is, the problems it solves and where to start.
Your app sends email, SMS, payments and webhooks. Testing them for real is slow, costs money and is risky: a test email reaches a real customer, an OTP needs a real phone and credits, a payment needs a sandbox account and a public URL for its notifications, and a Slack alert lands in the team channel.
SendMock is a local stand-in for all of those services. It runs as one small binary (or a Docker image) on your machine:
- Point your app at SendMock instead of the real SMTP server, SMS provider, payment gateway or API.
- See everything your app sent in a web UI: every email, SMS, verification code, HTTP call and payment.
- Get the answers back the way the real service would send them: delivery receipts, bounces, inbound replies, payment notifications and webhooks, signed like the provider signs them.
Now in beta. Install the beta or try the web UI in the live demo with sample data.
What it covers
| Area | What SendMock does | Read |
|---|---|---|
| catches mail over SMTP and the SendGrid, Mailgun, Postmark, Resend, SES and Brevo APIs; simulates delivery, bounces, complaints, opens and replies | ||
| SMS | Twilio and Vonage compatible APIs with Twilio's real test numbers, status callbacks, two-way replies and WhatsApp | SMS |
| Verify | Twilio Verify with codes you can read and outcomes you can force | Verify |
| HTTP Catcher | a catcher for any other call your app makes (Slack, Discord, push, third-party APIs), answered the way you choose | HTTP Catcher |
| Webhooks | sends events to your app automatically or by hand, shaped like the provider you use, with retries and replay | Webhooks |
| Payments | Stripe, PayPal, SSLCommerz and bKash test checkouts with real redirects and notifications, plus your own gateways | Payments |
| AI agents | a CLI, an MCP server and an agent skill, so an agent can set up and test everything | AI |
Where to start
- New here? Follow Getting started, then take the Tour of the app.
- Have a problem to solve? Find it in What can I test?.
- Want to know how the parts fit? Read How it all connects.
- Need something SendMock does not ship? See Advanced and Build it with AI.