The aeson package

[Tags: bsd3, library]

A JSON parsing and generation library optimized for ease of use and high performance.

Parsing performance with GHC 6.12.3 on a late 2010 MacBook Pro (2.66GHz Core i7), for mostly-English tweets from Twitter's JSON search API:

Handling heavily-escaped text is a little more work. Here is parsing performance with Japanese tweets, where much of the text is entirely Unicode-escaped:

Encoding performance on the same machine and data:

With GHC 7.0.2, the story is mixed: parsing is 20-40% slower than GHC 6.12.3, while encoding performance ranges from about the same to twice as fast (on numeric data).

(A note on naming: in Greek mythology, Aeson was the father of Jason.)

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Versions0.1.0.0,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, (info)
Change logNone available
Dependenciesattoparsec (>=, base (==4.*), blaze-builder (>=, bytestring, containers, deepseq (<1.2), ghc-prim, hashable, integer (==0.1.*), integer-gmp, mtl, old-locale, syb, text (>=, time, unordered-containers (>=, vector (>=0.7) [details]
CopyrightCopyright 2011 MailRank, Inc.
AuthorBryan O'Sullivan <>
MaintainerBryan O'Sullivan <>
CategoryText, Web, JSON
Home page
Bug tracker
Source repositoryhead: git clone
head: hg clone
UploadedWed Apr 13 17:47:02 UTC 2011 by BryanOSullivan
UpdatedWed Nov 11 15:05:32 UTC 2015 by phadej to revision 1
DistributionsDebian:, Fedora:, FreeBSD:, LTSHaskell:, NixOS:, Stackage:
Downloads228257 total (297 in last 30 days)
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StatusDocs uploaded by user
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Maintainers' corner

For package maintainers and hackage trustees

Readme for aeson-

Welcome to aeson

aeson is a fast Haskell library for working with JSON data.

Join in!

We are happy to receive bug reports, fixes, documentation enhancements, and other improvements.

Please report bugs via the github issue tracker.

Master git repository:

There's also a Mercurial mirror:

(You can create and contribute changes using either git or Mercurial.)


This library is written and maintained by Bryan O'Sullivan,