diff --git a/extra/spider/authors.txt b/extra/spider/authors.txt
new file mode 100644
index 0000000000..7c1b2f2279
--- /dev/null
+++ b/extra/spider/authors.txt
@@ -0,0 +1 @@
+Doug Coleman
diff --git a/extra/spider/spider.factor b/extra/spider/spider.factor
new file mode 100644
index 0000000000..7f68fe3a8f
--- /dev/null
+++ b/extra/spider/spider.factor
@@ -0,0 +1,91 @@
+! Copyright (C) 2008 Doug Coleman.
+! See http://factorcode.org/license.txt for BSD license.
+USING: accessors fry html.parser html.parser.analyzer
+http.client kernel tools.time sets assocs sequences
+concurrency.combinators io threads namespaces math multiline
+heaps math.parser inspector urls assoc-deques logging
+combinators.short-circuit continuations calendar prettyprint ;
+IN: spider
+
+TUPLE: spider base count max-count sleep max-depth secure? agent timeout
+filters spidered todo nonmatching initial-links ;
+
+TUPLE: spider-result url depth headers fetch-time parsed-html
+links processing-time ;
+
+: <spider> ( base -- spider )
+    >url
+    spider new
+        over >>base
+        swap 0 <unique-min-heap> [ heap-push ] keep >>todo
+        <unique-min-heap> >>nonmatching
+        0 >>max-depth
+        0 >>count
+        1/0. >>max-count
+        H{ } clone >>spidered ;
+
+<PRIVATE
+
+: apply-filters ( links spider -- links' )
+    filters>> [ '[ _ 1&& ] filter ] when* ;
+
+: add-todo ( links level spider -- )
+    tuck [ apply-filters ] 2dip
+    tuck
+    [ spidered>> keys diff ]
+    [ todo>> ] 2bi* '[ _ _ heap-push ] each ;
+
+: add-nonmatching ( links level spider -- )
+    nonmatching>> '[ _ _ heap-push ] each ;
+
+: relative-url? ( url -- ? ) protocol>> not ;
+
+: filter-base ( spider spider-result -- base-links nonmatching-links )
+    [ base>> host>> ] [ links>> prune ] bi*
+    [ host>> = ] with partition ;
+
+: add-spidered ( spider spider-result -- )
+    [ [ 1+ ] change-count ] dip
+    2dup [ spidered>> ] [ dup url>> ] bi* rot set-at
+    [ filter-base ] 2keep
+    depth>> 1+ swap
+    [ add-nonmatching ]
+    [ add-todo ] 2bi ;
+
+: print-spidering ( url depth -- )
+    "depth: " write number>string write
+    ", spidering: " write . yield ;
+
+: normalize-hrefs ( links -- links' )
+    [ >url ] map
+    spider get base>> swap [ derive-url ] with map ;
+
+: (spider-page) ( url depth -- spider-result )
+    2dup print-spidering
+    f pick spider get spidered>> set-at
+    over '[ _ http-get ] benchmark swap
+    [ parse-html dup find-hrefs normalize-hrefs ] benchmark
+    spider-result boa
+    dup describe ;
+
+: spider-page ( url depth -- )
+    (spider-page) spider get swap add-spidered ;
+
+\ spider-page ERROR add-error-logging
+
+: spider-sleep ( -- )
+    spider get sleep>> [ sleep ] when* ;
+
+PRIVATE>
+
+: run-spider ( spider -- spider )
+    "spider" [
+        dup spider [
+            [ todo>> ] [ max-depth>> ] bi
+            '[
+                _ <= spider get
+                [ count>> ] [ max-count>> ] bi < and
+            ] [ spider-page spider-sleep ] slurp-heap-when
+            spider get
+        ] with-variable
+    ] with-logging ;