Announcing our $18M Series A to Transform API Testing

Today we're thrilled to announce that Stage has raised $18 million in Series A funding led by Andreessen Horowitz, with continued participation from Sequoia Capital and angel investors from Stripe, Datadog, and Vercel.

Why We're Building Stage

Every engineering team faces the same challenge: how do you test edge cases, error states, and complex scenarios without risking production data?

The traditional approaches—mocking libraries, staging environments, feature flags—all have significant limitations:

• Mocking drifts from reality: Your mocks don't behave like the real thing
• Staging environments are expensive: And they're never quite the same as production
• Feature flags only toggle code paths: They can't change API responses

Stage takes a fundamentally different approach. By operating at the gateway level, we intercept and mutate API responses in real-time. This lets developers test any scenario they can imagine—without touching upstream systems.

What We've Built

In the year since our seed round, we've:

• Launched our public beta with 1,000+ companies
• Processed over 50 million API requests through our gateway
• Achieved 99.99% uptime
• Built integrations with major CI/CD platforms
• Achieved SOC 2 Type II certification

Our customers include engineering teams at companies ranging from early-stage startups to Fortune 500 enterprises.

What's Next

With this funding, we're investing in:

1. Platform capabilities: More powerful mutation rules, better debugging tools, and enhanced analytics
2. Enterprise features: SSO, audit logs, compliance controls, and dedicated support
3. Team growth: We're hiring across engineering, product, and go-to-market (check out our careers page)
4. Community: Open-sourcing key components and building integrations with the tools developers love

Thank You

To our customers who trusted us early, our team who's built something special, and our investors who believe in our vision—thank you.

We're just getting started. If you want to join us on this journey, get in touch.

— Sarah Chen, CEO & Co-founder