A collective list of free APIs
fast C++ library for linear algebra & scientific computing
OpenDDS is open source publish/subscribe middleware
Quantized transactions python3
Powerful new number types and numeric abstractions for Scala
High-performance TensorFlow library for quantitative finance
Finance library for C++
Investing Returns on the Market as a Whole
[DEPRECATED] Yahoo finance API is shut down by Yahoo!
Free Java components for Quantitative Finance and Algorithmic Trading