diff --git a/src/client/distren.h b/src/client/distren.h
--- a/src/client/distren.h
+++ b/src/client/distren.h
@@ -20,6 +20,48 @@
 #ifndef DISTREN_H
 #define DISTREN_H 1
 
+#include <stddef.h> /* size_t */
 
+typedef struct distren *distren_t;
+
+typedef void* (*distren_malloc_t)(size_t);
+typedef void (*distren_free_t)(void*);
+
+typedef struct distren_job *distren_job_t;
+
+/**
+ Initialize a libdistren handle. In the spirit of respecting client programs' choices,
+ this initialization function allows malloc() and free() compatible function pointers
+ to be passed.
+*/
+int distren_init_mf(distren_t *handle, distren_malloc_t mymalloc, distren_free_t myfree);
+
+/**
+ Initializes a libdistren handle using the system malloc() and free() implementation.
+*/
+int distren_init(distren_t *handle);
+
+/**
+ Submits a file to distren.
+ @param job must not refer to a valid job.
+ TODO: create a stream-based interface
+*/
+int distren_submit_file(distren_job_t *job, const char *filename);
+
+/*
+ TODO: extraction of a job-ID, retrieving job handle by job-ID, getting information
+ for a job handle, retrieving results of a job, callbacks for progress (i.e., job_is_finished callback)
+ -- threads?
+*/
+
+/**
+ Destroys and frees a job handle
+*/
+int distren_job_free(distren_job_t job);
+
+/**
+ Destroys and frees a libdistren handle
+*/
+int distren_free(distren_t handle);
 
 #endif