diff --git a/tokio/docs/ffi.md b/tokio/docs/ffi.md
new file mode 100644
index 000000000..7fecebb30
--- /dev/null
+++ b/tokio/docs/ffi.md
@@ -0,0 +1,2 @@
+# Tokio FFI
+
diff --git a/tokio/ffi/task.h b/tokio/ffi/task.h
new file mode 100644
index 000000000..1c374527b
--- /dev/null
+++ b/tokio/ffi/task.h
@@ -0,0 +1,10 @@
+struct Context {
+    void (*wake) (void*);
+
+};
+
+struct Task {
+    void* data;
+    void* (*poll) (void*);
+};
+
diff --git a/tokio/ffi/tokio.h b/tokio/ffi/tokio.h
new file mode 100644
index 000000000..defbac42f
--- /dev/null
+++ b/tokio/ffi/tokio.h
@@ -0,0 +1,51 @@
+#include <stdint.h>
+
+struct RuntimeUnstableOptions {
+    // unstable
+    bool enable_metrics_poll_count_histogram;
+    // unstable
+    size_t metrics_poll_count_histogram_buckets;
+    // unstable
+    struct timespec metrics_poll_count_histogram_resolution;
+
+    // unstable
+    uint8_t unhandled_panic;
+};
+
+struct RuntimeHooks {
+    void (*on_thread_park) (void);
+    void (*on_thread_unpark) (void);
+    void (*on_thread_start) (void);
+    void (*on_thread_stop) (void);
+};
+
+struct RuntimeOptions {
+    // unstable
+    bool disable_lifo_slot;
+
+    bool enable_time;
+    bool enable_io;
+
+    uint32_t event_interval;
+    uint32_t global_queue_interval;
+
+    size_t max_blocking_threads;
+
+    size_t max_io_events_per_tick;
+
+    uint8_t runtime_kind;
+
+    // todo rng_seed
+
+    bool start_paused;
+
+    struct timespec thread_keep_alive;
+
+    char* thread_name;
+    char* (*thread_name_fn) (void);
+    size_t thread_stack_size;
+
+    size_t worker_threads;
+};
+
+struct Runtime;
\ No newline at end of file