diff --git a/.gitignore b/.gitignore
index 4d308908..1b98c17b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,6 @@ pom.xml.asc
 !java/src/babashka/impl/LockFix.class
 !test-resources/babashka/src_for_classpath_test/foo.jar
 .cpcache
-reflection.json
+*reflection.json
 /tmp
 /reports
diff --git a/README.md b/README.md
index 5ac8d5c7..63ba3c0c 100644
--- a/README.md
+++ b/README.md
@@ -211,6 +211,7 @@ enumerated explicitly.
 - [`clojure.tools.cli`](https://github.com/clojure/tools.cli) aliased as `tools.cli`
 - [`clojure.data.csv`](https://github.com/clojure/data.csv) aliased as `csv`
 - [`cheshire.core`](https://github.com/dakrone/cheshire) aliased as `json`
+- [`cognitect.transit`](https://github.com/cognitect/transit-clj) aliased as `transit`
 
 A selection of java classes are available, see `babashka/impl/classes.clj`.
 
diff --git a/doc/dev.md b/doc/dev.md
index c97f7f8f..4fefb30b 100644
--- a/doc/dev.md
+++ b/doc/dev.md
@@ -53,6 +53,9 @@ Then run:
 
 Keep notes here about how adding libraries and classes to Babashka affects the binary size.
 
+2020/03/20 Added transit write, writer, read, reader
+42004796 - 41025212 = 980kb added (305kb zipped).
+
 2020/03/19 Added java.lang.NumberFormatException, java.lang.RuntimeException,
 java.util.MissingResourceException and java.util.Properties to support
 [cprop](https://github.com/tolitius/cprop/).
diff --git a/project.clj b/project.clj
index d28931e5..becb1397 100644
--- a/project.clj
+++ b/project.clj
@@ -18,7 +18,8 @@
                  [org.clojure/tools.cli "0.4.2"]
                  [org.clojure/data.csv "1.0.0"]
                  [cheshire "5.10.0"]
-                 [fipp "0.6.22"]]
+                 [fipp "0.6.22"]
+                 [com.cognitect/transit-clj "1.0.324"]]
   :profiles {:test {:dependencies [[clj-commons/conch "0.9.2"]
                                    [com.clojure-goes-fast/clj-async-profiler "0.4.0"]]}
              :uberjar {:global-vars {*assert* false}
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index 25a057e4..4a4e404a 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -198,7 +198,9 @@
                    (instance? java.io.ByteArrayOutputStream v)
                    java.io.ByteArrayOutputStream
                    (instance? java.security.MessageDigest v)
-                   java.security.MessageDigest)))))
+                   java.security.MessageDigest
+                   (instance? java.io.InputStream v)
+                   java.io.InputStream)))))
 
 (def class-map (gen-class-map))
 
diff --git a/src/babashka/impl/transit.clj b/src/babashka/impl/transit.clj
new file mode 100644
index 00000000..e7c84311
--- /dev/null
+++ b/src/babashka/impl/transit.clj
@@ -0,0 +1,12 @@
+(ns babashka.impl.transit
+  (:require [cognitect.transit :as transit]
+            [sci.impl.namespaces :refer [copy-var]]
+            [sci.impl.vars :as vars]))
+
+(def tns (vars/->SciNamespace 'cognitect.transit nil))
+
+(def transit-namespace
+  {'write (copy-var transit/write tns)
+   'writer (copy-var transit/writer tns)
+   'read (copy-var transit/read tns)
+   'reader (copy-var transit/reader tns)})
diff --git a/src/babashka/main.clj b/src/babashka/main.clj
index a224eed3..3f9d1d37 100644
--- a/src/babashka/main.clj
+++ b/src/babashka/main.clj
@@ -19,6 +19,7 @@
    [babashka.impl.socket-repl :as socket-repl]
    [babashka.impl.test :as t]
    [babashka.impl.tools.cli :refer [tools-cli-namespace]]
+   [babashka.impl.transit :refer [transit-namespace]]
    [babashka.wait :as wait]
    [clojure.edn :as edn]
    [clojure.java.io :as io]
@@ -26,11 +27,11 @@
    [clojure.string :as str]
    [sci.addons :as addons]
    [sci.core :as sci]
-   [sci.impl.interpreter :refer [eval-string* eval-form]]
+   [sci.impl.interpreter :refer [eval-string*]]
    [sci.impl.opts :as sci-opts]
+   [sci.impl.types :as sci-types]
    [sci.impl.unrestrict :refer [*unrestricted*]]
-   [sci.impl.vars :as vars]
-   [sci.impl.types :as sci-types])
+   [sci.impl.vars :as vars])
   (:gen-class))
 
 (binding [*unrestricted* true]
@@ -234,7 +235,8 @@ Everything after that is bound to *command-line-args*."))
     async clojure.core.async
     csv clojure.data.csv
     json cheshire.core
-    curl babashka.curl})
+    curl babashka.curl
+    transit cognitect.transit})
 
 (def cp-state (atom nil))
 
@@ -265,7 +267,8 @@ Everything after that is bound to *command-line-args*."))
    'clojure.test t/clojure-test-namespace
    'babashka.classpath {'add-classpath add-classpath*}
    'clojure.pprint pprint-namespace
-   'babashka.curl curl-namespace})
+   'babashka.curl curl-namespace
+   'cognitect.transit transit-namespace})
 
 (def bindings
   {'java.lang.System/exit exit ;; override exit, so we have more control
diff --git a/test-resources/babashka/transit.clj b/test-resources/babashka/transit.clj
new file mode 100644
index 00000000..3d3bda6a
--- /dev/null
+++ b/test-resources/babashka/transit.clj
@@ -0,0 +1,18 @@
+(require '[cognitect.transit :as transit])
+(import [java.io ByteArrayInputStream ByteArrayOutputStream])
+
+;; Write data to a stream
+(def out (ByteArrayOutputStream. 4096))
+(def writer (transit/writer out :json))
+(transit/write writer "foo")
+(transit/write writer {:a [1 2]})
+
+;; Take a peek at the JSON
+(.toString out)
+;; => "{\"~#'\":\"foo\"} [\"^ \",\"~:a\",[1,2]]"
+
+;; Read data from a stream
+(def in (ByteArrayInputStream. (.toByteArray out)))
+(def reader (transit/reader in :json))
+(prn (transit/read reader))  ;; => "foo"
+(prn (transit/read reader))  ;; => {:a [1 2]}
diff --git a/test/babashka/main_test.clj b/test/babashka/main_test.clj
index c4a90a47..ac98ab9a 100644
--- a/test/babashka/main_test.clj
+++ b/test/babashka/main_test.clj
@@ -29,7 +29,7 @@
 
 (deftest main-test
   (testing "-io behaves as identity"
-    (= "foo\nbar\n" (test-utils/bb "foo\nbar\n" "-io" "*input*")))
+    (is (= "foo\nbar\n" (test-utils/bb "foo\nbar\n" "-io" "*input*"))))
   (testing "if and when"
     (is (= 1 (bb 0 '(if (zero? *input*) 1 2))))
     (is (= 2 (bb 1 '(if (zero? *input*) 1 2))))
@@ -355,6 +355,9 @@
     (is (= :clojure.string/foo
            (bb nil "(ns foo (:require [clojure.string :as str])) (read-string \"::str/foo\")")))))
 
+(deftest available-stream-test
+  (is (= 0 (bb nil "(.available System/in)"))))
+
 ;;;; Scratch
 
 (comment
diff --git a/test/babashka/transit_test.clj b/test/babashka/transit_test.clj
new file mode 100644
index 00000000..86523771
--- /dev/null
+++ b/test/babashka/transit_test.clj
@@ -0,0 +1,13 @@
+(ns babashka.transit-test
+  (:require
+   [babashka.test-utils :as test-utils]
+   [clojure.java.io :as io]
+   [clojure.test :as t :refer [deftest is]]))
+
+(defn bb [& args]
+  (apply test-utils/bb nil (map str args)))
+
+(deftest transit-test
+  (is (= "\"foo\"\n{:a [1 2]}\n"
+         (bb (format "(load-file \"%s\")"
+                     (.getPath (io/file "test-resources" "babashka" "transit.clj")))))))