diff --git a/docs/manual/treefile.md b/docs/manual/treefile.md
index a4fdef3c..030130ad 100644
--- a/docs/manual/treefile.md
+++ b/docs/manual/treefile.md
@@ -196,3 +196,13 @@ It supports the following parameters:
    and further, we don't want to encourage `/sysroot` to be writable.
    For host system composes, we recommend turning this on; it's left off
    by default to ease the transition.
+
+Experimental options
+--------
+
+All options listed here are subject to change or removal in a future
+version of `rpm-ostree`.
+
+ * `ex-jigdo-spec`: string, optional:  If specified, will also cause
+   a run of `rpm-ostree ex commit2jigdo` on changes.  Also requires the
+   `--ex-jigdo-output-rpm` commandline option.
diff --git a/src/app/rpmostree-compose-builtin-tree.c b/src/app/rpmostree-compose-builtin-tree.c
index f6b02548..399a79b3 100644
--- a/src/app/rpmostree-compose-builtin-tree.c
+++ b/src/app/rpmostree-compose-builtin-tree.c
@@ -39,6 +39,7 @@
 #include "rpmostree-bwrap.h"
 #include "rpmostree-core.h"
 #include "rpmostree-json-parsing.h"
+#include "rpmostree-jigdo-build.h"
 #include "rpmostree-postprocess.h"
 #include "rpmostree-passwd-util.h"
 #include "rpmostree-libbuiltin.h"
@@ -55,6 +56,7 @@ static gboolean opt_cache_only;
 static gboolean opt_ex_unified_core;
 static char *opt_proxy;
 static char *opt_output_repodata_dir;
+static char *opt_ex_jigdo_output_rpm;
 static char **opt_metadata_strings;
 static char *opt_metadata_json;
 static char *opt_repo;
@@ -75,6 +77,7 @@ static GOptionEntry install_option_entries[] = {
   { "cachedir", 0, 0, G_OPTION_ARG_STRING, &opt_cachedir, "Cached state", "CACHEDIR" },
   { "download-only", 0, 0, G_OPTION_ARG_NONE, &opt_download_only, "Like --dry-run, but download RPMs as well; requires --cachedir", NULL },
   { "ex-unified-core", 0, 0, G_OPTION_ARG_NONE, &opt_ex_unified_core, "Use new \"unified core\" codepath", NULL },
+  { "ex-jigdo-output-rpm", 0, 0, G_OPTION_ARG_STRING, &opt_ex_jigdo_output_rpm, "Directory to write jigdoRPM", NULL },
   { "proxy", 0, 0, G_OPTION_ARG_STRING, &opt_proxy, "HTTP proxy", "PROXY" },
   { "dry-run", 0, 0, G_OPTION_ARG_NONE, &opt_dry_run, "Just print the transaction and exit", NULL },
   { "output-repodata-dir", 0, 0, G_OPTION_ARG_STRING, &opt_output_repodata_dir, "Save downloaded repodata in DIR", "DIR" },
@@ -111,6 +114,7 @@ typedef struct {
   OstreeRepo *pkgcache_repo;
   OstreeRepoDevInoCache *devino_cache;
   char *ref;
+  char *jigdo_spec;
   char *previous_checksum;
 
   JsonParser *treefile_parser;
@@ -138,6 +142,7 @@ rpm_ostree_tree_compose_context_free (RpmOstreeTreeComposeContext *ctx)
   g_clear_object (&ctx->pkgcache_repo);
   g_clear_pointer (&ctx->devino_cache, (GDestroyNotify)ostree_repo_devino_cache_unref);
   g_free (ctx->ref);
+  g_free (ctx->jigdo_spec);
   g_free (ctx->previous_checksum);
   g_clear_object (&ctx->treefile_parser);
   g_clear_pointer (&ctx->serialized_treefile, (GDestroyNotify)g_bytes_unref);
@@ -752,6 +757,11 @@ rpm_ostree_compose_context_new (const char    *treefile_pathstr,
 
   if (opt_workdir_tmpfs)
     g_print ("note: --workdir-tmpfs is deprecated and will be ignored\n");
+
+  /* jigdo implies unified core mode currently */
+  if (opt_ex_jigdo_output_rpm)
+    opt_ex_unified_core = TRUE;
+
   if (opt_ex_unified_core)
     {
       if (opt_workdir)
@@ -861,6 +871,13 @@ rpm_ostree_compose_context_new (const char    *treefile_pathstr,
   if (!self->ref)
     return FALSE;
 
+  g_autoptr(GFile) treefile_dir = g_file_get_parent (self->treefile_path);
+  const char *jigdo_spec = NULL;
+  if (!_rpmostree_jsonutil_object_get_optional_string_member (self->treefile, "ex-jigdo-spec", &jigdo_spec, error))
+    return FALSE;
+  if (jigdo_spec)
+    self->jigdo_spec = g_build_filename (gs_file_get_path_cached (treefile_dir), jigdo_spec, NULL);
+
   *out_context = g_steal_pointer (&self);
   return TRUE;
 }
@@ -1187,6 +1204,17 @@ impl_commit_tree (RpmOstreeTreeComposeContext *self,
                                  &new_revision, cancellable, error))
     return FALSE;
 
+  if (opt_ex_jigdo_output_rpm)
+    {
+      if (!self->jigdo_spec)
+        return glnx_throw (error, "No ex-jigdo-spec provided");
+      if (!rpmostree_commit2jigdo (self->repo, self->pkgcache_repo,
+                                   new_revision, self->jigdo_spec,
+                                   opt_ex_jigdo_output_rpm,
+                                   cancellable, error))
+        return FALSE;
+    }
+
   /* --write-commitid-to overrides writing the ref */
   if (self->ref && !opt_write_commitid_to)
     {
diff --git a/tests/compose-tests/test-compose2jigdo.sh b/tests/compose-tests/test-compose2jigdo.sh
new file mode 100755
index 00000000..18c846ff
--- /dev/null
+++ b/tests/compose-tests/test-compose2jigdo.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+# Test rpm-ostree compose tree --ex-jigdo-output-rpm
+
+set -xeuo pipefail
+
+dn=$(cd $(dirname $0) && pwd)
+. ${dn}/libcomposetest.sh
+. ${dn}/../common/libtest.sh
+
+prepare_compose_test "compose2jigdo"
+pysetjsonmember "ex-jigdo-spec" '"fedora-atomic-host-oirpm.spec"'
+mkdir cache
+mkdir jigdo-output
+runcompose --ex-jigdo-output-rpm $(pwd)/jigdo-output --cachedir $(pwd)/cache --add-metadata-string version=42.0
+rev=$(ostree --repo=repo-build rev-parse ${treeref})
+find jigdo-output -name '*.rpm' | tee rpms.txt
+assert_file_has_content rpms.txt 'fedora-atomic-host-42.0.*x86_64'
+grep 'fedora-atomic-host.*x86_64\.rpm' rpms.txt | while read p; do
+    rpm -qp --provides ${p} >>provides.txt
+done
+assert_file_has_content_literal provides.txt "rpmostree-jigdo-commit(${rev})"
+echo "ok compose2jigdo"