Spillway: API Load Testing
Load & stress testing tool
Only for Mac
Free · In‑App Purchases
Mac
Load-test your APIs from a native macOS app. Build request scenarios, ramp virtual users or request rates, and watch live percentile, throughput, and error charts.
Spillway is a native macOS load and performance testing tool for HTTP APIs and web services. Think JMeter, k6, or Gatling — but as a first-class Mac document app. No scripts, no YAML, no terminal required. Design a test plan visually, press Run, and watch the results stream in live.
BUILT FOR THE MAC
Every test plan is a document you open, edit, save, and share. Full undo/redo, a familiar layout, and native SwiftUI throughout — it feels like a Mac app because it is one.
MODEL REAL-WORLD LOAD
• User-based model — simulate a fixed pool of virtual users
• Throughput-based model — drive a target request rate (requests per second)
• Ramp load up or down over time to find your breaking point
• Constant, spike, and long-running soak profiles
BUILD REALISTIC SCENARIOS
• Sequence HTTP requests with full control over method, headers, query parameters, and body
• Loops, conditions, and think-time pauses
• Extract values from responses with regex or JSON queries, then feed them into later requests
• Data-driven testing from CSV input
• Import your existing JMeter (.jmx) test plans
• Dynamic variables with a token expression language and built-in functions
• OAuth 2.0 authentication and automatic cookie/session handling
SEE WHAT'S HAPPENING, LIVE
• Response-time percentiles (p50 / p90 / p95 / p99)
• Throughput and error-rate charts that update as the test runs
• Per-request timing and full request/response inspection
• CPU and memory telemetry for your load generators
• Compare executions to see the differences in performance profile
Whether you're chasing a latency regression, validating capacity before a launch, or running an overnight soak test, Spillway gives you a fast, native, friction-free way to put your services under pressure — and understand exactly how they respond.
End-user licence agreement: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy policy: https://spillwayapp.com/privacy
Ratings & Reviews
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Minor bug fixes
The developer, Craig EDWARDS, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Craig EDWARDS
- Size
- 15.7 MB
- Category
- Developer Tools
- Compatibility
Requires macOS 15.0 or later.
- Mac
Requires macOS 15.0 or later.
- Mac
- Languages
English and 14 more
- English, Arabic, Bengali, French, German, Hindi, Indonesian, Italian, Japanese, Portuguese, Russian, Simplified Chinese, Spanish, Traditional Chinese, Urdu
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Spillway Advanced $44.99
- Copyright
- © 2026 Spillway