diff --git a/README.md b/README.md
index a865b60..fb42c3f 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,20 @@ The reference implementation, specification, template, and tests for creating an
 The reference implementation is completely in-memory.
 
 See [Help Wanted: Database Plugins (for saving certs)](https://github.com/Daplie/node-letsencrypt/issues/39)
+
+API
+===
+
+```
+* getOptions()
+* accounts.
+  * checkKeypair(opts, cb)
+  * setKeypair(opts, keypair, cb)
+  * check(opts, cb)
+  * set(opts, reg, cb)
+* certificates.
+  * checkKeypair(opts, cb)
+  * setKeypair(opts, keypair, cb)
+  * check(opts, cb)
+  * set(opts, reg, cb)
+```