JSON parsing in D has come a long way, especially when you look at it from the efficiency angle as a popular benchmark does that has been forked by well known D contributers like Martin Nowak or Sönke Ludwig.
The test is pretty simple: Parse a JSON object, containing an array of 1_000_000 3D coordinates in the range [0..1) and average them. The performance of std.json in parsing those was horrible still in the DMD 2.066 days*: DMD : 41.44s, 934.9Mb Gdc : 29.64s, 929.7Mb Python : 12.30s, 1410.2Mb Ruby : 13.80s, 2101.2Mb Then with 2.067 std.json got a major 3x speed improvement and rivaled the popular dynamic languages Ruby and Python: DMD : 13.02s, 1324.2Mb In the mean time several other D JSON libraries appeared with varying focus on performance or API: Medea : 56.75s, 1753.6Mb (GDC) libdjson : 24.47s, 1060.7Mb (GDC) stdx.data.json: 2.76s, 207.1Mb (LDC) Yep, that's right. stdx.data.json's pull parser finally beats the dynamic languages with native efficiency. (I used the default options here that provide you with an Exception and line number on errors.) A few days ago I decided to get some practical use out of my pet project 'fast' by implementing a JSON parser myself, that could rival even the by then fastest JSON parser, RapidJSON. The result can be seen in the benchmark results right now: https://github.com/kostya/benchmarks#json fast: 0.34s, 226.7Mb (GDC) RapidJSON: 0.79s, 687.1Mb (GCC) (* Timings from my computer, Haswell CPU, Linux amd64.) -- Marco