diff --git a/build.py b/build.py
index b5b9e929..a27f272f 100644
--- a/build.py
+++ b/build.py
@@ -34,7 +34,6 @@ cxxlibrary(
         "./lib/fluxsink/scpfluxsink.cc",
         "./lib/fluxsink/vcdfluxsink.cc",
         "./lib/fluxsource/a2rfluxsource.cc",
-        "./lib/fluxsource/catweasel.cc",
         "./lib/fluxsource/cwffluxsource.cc",
         "./lib/fluxsource/dmkfluxsource.cc",
         "./lib/fluxsource/erasefluxsource.cc",
@@ -43,7 +42,6 @@ cxxlibrary(
         "./lib/fluxsource/flx.cc",
         "./lib/fluxsource/flxfluxsource.cc",
         "./lib/fluxsource/hardwarefluxsource.cc",
-        "./lib/fluxsource/kryoflux.cc",
         "./lib/fluxsource/kryofluxfluxsource.cc",
         "./lib/fluxsource/memoryfluxsource.cc",
         "./lib/fluxsource/scpfluxsource.cc",
@@ -144,10 +142,8 @@ cxxlibrary(
         "lib/decoders/rawbits.h": "./lib/decoders/rawbits.h",
         "lib/encoders/encoders.h": "./lib/encoders/encoders.h",
         "lib/fluxsink/fluxsink.h": "./lib/fluxsink/fluxsink.h",
-        "lib/fluxsource/catweasel.h": "lib/fluxsource/catweasel.h",
         "lib/fluxsource/fluxsource.h": "lib/fluxsource/fluxsource.h",
         "lib/fluxsource/flx.h": "lib/fluxsource/flx.h",
-        "lib/fluxsource/kryoflux.h": "lib/fluxsource/kryoflux.h",
         "lib/imagereader/imagereader.h": "./lib/imagereader/imagereader.h",
         "lib/imagewriter/imagewriter.h": "./lib/imagewriter/imagewriter.h",
         "lib/readerwriter.h": "./lib/readerwriter.h",
diff --git a/lib/external/build.py b/lib/external/build.py
index 94ff96ee..1715d5ae 100644
--- a/lib/external/build.py
+++ b/lib/external/build.py
@@ -9,12 +9,16 @@ cxxlibrary(
     srcs=[
         "./ldbs.cc",
         "./fl2.cc",
+        "./kryoflux.cc",
+        "./catweasel.cc",
     ],
     hdrs={
         "lib/external/ldbs.h": "./ldbs.h",
         "lib/external/a2r.h": "./a2r.h",
         "lib/external/scp.h": "./scp.h",
         "lib/external/fl2.h": "./fl2.h",
+        "lib/external/kryoflux.h": "./kryoflux.h",
+        "lib/external/catweasel.h": "./catweasel.h",
     },
     deps=["lib/core", ".+fl2_proto_lib", "lib/data"],
 )
diff --git a/lib/fluxsource/catweasel.cc b/lib/external/catweasel.cc
similarity index 95%
rename from lib/fluxsource/catweasel.cc
rename to lib/external/catweasel.cc
index 0210d543..cafa90d3 100644
--- a/lib/fluxsource/catweasel.cc
+++ b/lib/external/catweasel.cc
@@ -1,7 +1,7 @@
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
 #include "lib/core/bytes.h"
-#include "lib/fluxsource/catweasel.h"
+#include "lib/external/catweasel.h"
 
 std::unique_ptr<Fluxmap> decodeCatweaselData(
     const Bytes& bytes, nanoseconds_t clock)
diff --git a/lib/fluxsource/catweasel.h b/lib/external/catweasel.h
similarity index 100%
rename from lib/fluxsource/catweasel.h
rename to lib/external/catweasel.h
diff --git a/lib/fluxsource/kryoflux.cc b/lib/external/kryoflux.cc
similarity index 99%
rename from lib/fluxsource/kryoflux.cc
rename to lib/external/kryoflux.cc
index 0128de9d..fb9cc8e2 100644
--- a/lib/fluxsource/kryoflux.cc
+++ b/lib/external/kryoflux.cc
@@ -1,6 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
-#include "kryoflux.h"
+#include "lib/external/kryoflux.h"
 #include "protocol.h"
 #include <fstream>
 #include <sys/types.h>
diff --git a/lib/fluxsource/kryoflux.h b/lib/external/kryoflux.h
similarity index 100%
rename from lib/fluxsource/kryoflux.h
rename to lib/external/kryoflux.h
diff --git a/lib/fluxsource/cwffluxsource.cc b/lib/fluxsource/cwffluxsource.cc
index 53d9f28a..49bfba77 100644
--- a/lib/fluxsource/cwffluxsource.cc
+++ b/lib/fluxsource/cwffluxsource.cc
@@ -2,7 +2,7 @@
 #include "lib/data/fluxmap.h"
 #include "lib/fluxsource/fluxsource.pb.h"
 #include "lib/fluxsource/fluxsource.h"
-#include "lib/fluxsource/catweasel.h"
+#include "lib/external/catweasel.h"
 #include "lib/config/proto.h"
 #include <fstream>
 
diff --git a/lib/fluxsource/dmkfluxsource.cc b/lib/fluxsource/dmkfluxsource.cc
index 4771b372..22b16216 100644
--- a/lib/fluxsource/dmkfluxsource.cc
+++ b/lib/fluxsource/dmkfluxsource.cc
@@ -2,7 +2,7 @@
 #include "lib/data/fluxmap.h"
 #include "lib/fluxsource/fluxsource.pb.h"
 #include "lib/fluxsource/fluxsource.h"
-#include "lib/fluxsource/catweasel.h"
+#include "lib/external/catweasel.h"
 #include "lib/config/proto.h"
 #include "lib/core/logger.h"
 #include <fstream>
diff --git a/lib/fluxsource/flx.cc b/lib/fluxsource/flx.cc
index 110112d5..c13fd41e 100644
--- a/lib/fluxsource/flx.cc
+++ b/lib/fluxsource/flx.cc
@@ -1,6 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
-#include "kryoflux.h"
+#include "lib/external/kryoflux.h"
 #include "protocol.h"
 #include "lib/fluxsource/flx.h"
 
diff --git a/lib/fluxsource/kryofluxfluxsource.cc b/lib/fluxsource/kryofluxfluxsource.cc
index 29633ce8..e48e2c45 100644
--- a/lib/fluxsource/kryofluxfluxsource.cc
+++ b/lib/fluxsource/kryofluxfluxsource.cc
@@ -1,6 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
-#include "kryoflux.h"
+#include "lib/external/kryoflux.h"
 #include "lib/fluxsource/fluxsource.pb.h"
 #include "lib/fluxsource/fluxsource.h"
 
diff --git a/lib/fluxsource/scpfluxsource.cc b/lib/fluxsource/scpfluxsource.cc
index 00b64179..2d6a1ab2 100644
--- a/lib/fluxsource/scpfluxsource.cc
+++ b/lib/fluxsource/scpfluxsource.cc
@@ -1,6 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
-#include "kryoflux.h"
+#include "lib/external/kryoflux.h"
 #include "lib/fluxsource/fluxsource.pb.h"
 #include "lib/core/utils.h"
 #include "lib/fluxsource/fluxsource.h"
diff --git a/tests/kryoflux.cc b/tests/kryoflux.cc
index 3887f14b..70256b13 100644
--- a/tests/kryoflux.cc
+++ b/tests/kryoflux.cc
@@ -3,7 +3,7 @@
 #include <stdlib.h>
 #include "lib/core/globals.h"
 #include "lib/data/fluxmap.h"
-#include "lib/fluxsource/kryoflux.h"
+#include "lib/external/kryoflux.h"
 
 static void test_convert(const Bytes& kryofluxbytes, const Bytes& fluxmapbytes)
 {