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High-performance serialization library for Clojure
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Current semantic version:

[com.taoensso/nippy "1.0.1"]

Nippy, a Clojure serialization library

Clojure's rich data types are awesome. And its reader allows you to take your data just about anywhere. But the reader can be painfully slow when you've got a lot of data to crunch (like when you're serializing to a database).

Nippy is an attempt to provide a drop-in, high-performance alternative to the reader. It's a fork of Deep-Freeze and is used as the Carmine Redis client serializer.

What's In The Box?

  • Small, uncomplicated all-Clojure library.
  • Good performance.
  • Comprehesive, extensible support for all major data types.
  • Reader-fallback for difficult/future types (including Clojure 1.4+ tagged literals).
  • Full test coverage for every supported type.
  • Snappy integrated de/compression for efficient storage and network transfer.

Getting Started


Depend on Nippy in your project.clj:

[com.taoensso/nippy "1.0.1"]

and require the library:

(ns my-app (:require [taoensso.nippy :as nippy]))


As an example of what Nippy can do, let's take a look at its own reference stress data:

{:bytes        (byte-array [(byte 1) (byte 2) (byte 3)])
 :nil          nil
 :boolean      true

 :char-utf8    \ಬ
 :string-utf8  "ಬಾ ಇಲ್ಲಿ ಸಂಭವಿಸ"
 :string-long  (apply str (range 1000))
 :keyword      :keyword
 :ns-keyword   ::keyword

 :list         (list 1 2 3 4 5 (list 6 7 8 (list 9 10)))
 :list-quoted  '(1 2 3 4 5 (6 7 8 (9 10)))
 :list-empty   (list)
 :vector       [1 2 3 4 5 [6 7 8 [9 10]]]
 :vector-empty []
 :map          {:a 1 :b 2 :c 3 :d {:e 4 :f {:g 5 :h 6 :i 7}}}
 :map-empty    {}
 :set          #{1 2 3 4 5 #{6 7 8 #{9 10}}}
 :set-empty    #{}
 :meta         (with-meta {:a :A} {:metakey :metaval})
 :queue        (-> (PersistentQueue/EMPTY) (conj :a :b :c :d :e :f :g))
 :queue-empty  (PersistentQueue/EMPTY)
 :coll         (repeatedly 1000 rand)

 :byte         (byte 16)
 :short        (short 42)
 :integer      (int 3)
 :long         (long 3)
 :bigint       (bigint 31415926535897932384626433832795)

 :float        (float 3.14)
 :double       (double 3.14)
 :bigdec       (bigdec 3.1415926535897932384626433832795)

 :ratio        22/7

 ;; Clojure 1.4+
 ;; :tagged-uuid  (java.util.UUID/randomUUID)
 ;; :tagged-date  (java.util.Date.)

Serialize it:

(def frozen-stress-data (nippy/freeze-to-bytes nippy/stress-data))
=> #<byte[] [B@3253bcf3>

Deserialize it:

(nippy/thaw-from-bytes frozen-stress-data)
=> {:bytes        (byte-array [(byte 1) (byte 2) (byte 3)])
    :nil          nil
    :boolean      true
    <...> }

Couldn't be simpler!


Performance comparison chart

Data size chart

Detailed benchmark information is available on Google Docs.

Nippy Supports the ClojureWerkz and CDS Project Goals

ClojureWerkz is a growing collection of open-source, batteries-included Clojure libraries that emphasise modern targets, great documentation, and thorough testing.

CDS (Clojure Documentation Site) is a contributor-friendly community project aimed at producing top-notch Clojure tutorials and documentation.

Contact & Contribution

Reach me (Peter Taoussanis) at ptaoussanis at for questions/comments/suggestions/whatever. I'm very open to ideas if you have any! I'm also on Twitter: @ptaoussanis.


Copyright © 2012 Peter Taoussanis. Distributed under the Eclipse Public License, the same as Clojure.

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