diff --git a/Makefile b/Makefile
index c35ac35..4f49b7d 100644
--- a/Makefile
+++ b/Makefile
@@ -17,9 +17,16 @@ logarion.cmx: src/logarion.ml ymd.cmx
 	ymd.cmx src/logarion.ml
 
 ymd.cmx: src/ymd.ml
+	ocamlfind ocamlc -c -o ymd.cmi -linkpkg \
+	-package batteries,omd,lens,lens.ppx_deriving,ptime,re \
+	src/ymd.mli
 	ocamlfind ocamlopt -c -o ymd.cmx -linkpkg \
 	-package batteries,omd,lens,lens.ppx_deriving,ptime,re \
 	src/ymd.ml
 
+ymd.mli: src/ymd.ml
+	ocamlfind ocamlc -i src/ymd.ml \
+	-package batteries,omd,lens,lens.ppx_deriving,ptime,re > src/ymd.mli
+
 clean:
 	rm -f src/*.{cmx,cmi,o} *.{cmx,cmi,o}
diff --git a/src/ymd.mli b/src/ymd.mli
new file mode 100644
index 0000000..5eedd16
--- /dev/null
+++ b/src/ymd.mli
@@ -0,0 +1,66 @@
+
+
+type author = { name : string; email : string; }
+type date = { edited : Ptime.t option; published : Ptime.t option; }
+type meta = {
+  title : string;
+  author : author;
+  date : date;
+  categories : string list;
+  topics : string list;
+  keywords : string list;
+  series : string list;
+  abstract : string;
+}
+type ymd = { meta : meta; body : string; }
+
+val blank_meta : meta
+val blank_ymd : ymd
+
+val filename_of_title : string -> string
+(** get how a file should be named according to a title [string] *)
+
+val filename : ymd -> string
+(** get how a file should be named based on a [ymd] value *)
+
+(** {1 Conversions from and to string} *)
+
+val of_string : string -> ymd
+(** convert a string containing a ymd buffer to [ymd] **)
+
+val to_string : ymd -> string
+(** convert a ymd to a [string] *)
+
+val meta_of_yaml : string -> meta
+val with_kv : ymd -> string * string -> ymd
+
+val trim_str : string -> string
+val list_of_csv : string -> string list
+val of_str : 'a -> ('a, string) Lens.t -> string -> 'a
+val of_str_list : 'a -> ('a, string list) Lens.t -> string -> 'a
+
+val meta_pair_of_string : string -> string * string
+val with_meta_kv : meta -> string * string -> meta
+
+(** {1 Conversions from and to date) *)
+
+val rfc_string_of : Ptime.t option -> string
+val date_of : string -> Ptime.t option
+val date_string : ymd -> Ptime.t option
+                                                                
+(** {1 Lenses for accessing [ymd] record fields} *)
+
+val author_name : (author, string) Lens.t
+val author_email : (author, string) Lens.t
+val date_edited : (date, Ptime.t option) Lens.t
+val date_published : (date, Ptime.t option) Lens.t
+val meta_title : (meta, string) Lens.t
+val meta_author : (meta, author) Lens.t
+val meta_date : (meta, date) Lens.t
+val meta_categories : (meta, string list) Lens.t
+val meta_topics : (meta, string list) Lens.t
+val meta_keywords : (meta, string list) Lens.t
+val meta_series : (meta, string list) Lens.t
+val meta_abstract : (meta, string) Lens.t
+val ymd_meta : (ymd, meta) Lens.t
+val ymd_body : (ymd, string) Lens.t