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A simple, fast HTTP performance-testing tool
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apib: API Bench

This is a tool that makes it easy to test API servers. It is supported for Unix systems that include the Apache Portable Runtime and OpenSSL. That includes implementations of Linux, Windows under Cygwin, and Apple OS X.


apib has been fairly stable for a little while now. Please submit issues or pull requests if you find that you'd like it to do more within reason!

Current Version



Running apib can be as simple as:

apib -c 100 -d 60

The command above will hammer "" as fast as it can for up to 60 seconds using 100 concurrent network connections.


On the Mac, you can now install via Homebrew:

brew install apib

Otherwise, you can build it yourself from source.

See additional documentation for more:


apib has most of the features of Apache Bench (ab), but is also intended as a more modern replacement. In particular, it supports:

  • Proper HTTP 1.1 support including keep-alives and chunked encoding
  • Ability to spawn multiple I/O threads to take advantage of multiple CPU cores
  • Support for POST and PUT of large objects
  • Support for OAuth 1.0 signatures
  • Ability to output results to a file so they may be automated
  • Remote CPU monitoring

In addition, like "ab," it also supports:

  • A simple command-line interface
  • Few dependencies, so it may be easily built and deployed
  • Non-blocking I/O for high concurrency


  • apr -- makes it more portable to Linux, Solaris, Macintosh and others
  • openssl -- because we need SSL

Any reasonable platform will have both of these.


  1. Spawn one I/O thread per CPU (configured by user)
  2. Allocate a subset of connections to each, and in each:
  3. Start event loop
  4. If total number of connections < C, spawn a connection
  5. Execute HTTP state machine -- connecting, sending, receiving, sending
  6. When connections close, replace them to maintain C connections open
  7. Record results in a shared area
  8. Back in main thread, report on shared results periodically
  9. Time in main thread and signal workers to stop eventually
  10. Report to screen and to file
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