diff --git a/README.md b/README.md
index f45326c..589d1cd 100644
--- a/README.md
+++ b/README.md
@@ -6,18 +6,82 @@ Used to construct build tools for [`angular-gettext`](https://github.com/rubenv/
 
 [![Build Status](https://travis-ci.org/rubenv/grunt-angular-gettext.png?branch=master)](https://travis-ci.org/rubenv/angular-gettext-tools)
 
-Implementations:
+## Usage
+
+You probably want to use one of the build plugins that wrap this library
+instead. Current implementations:
 
 * [Grunt plugin](https://github.com/rubenv/grunt-angular-gettext)
 * [Gulp plugin](https://github.com/gabegorelick/gulp-angular-gettext)
 
-Check the website for usage instructions: [http://angular-gettext.rocketeer.be/](http://angular-gettext.rocketeer.be/).
+## API
+
+`angular-gettext-tools` has two components: an `Extractor` for extracting
+translatable strings into a [POT file](http://www.icanlocalize.com/site/tutorials/how-to-translate-with-gettext-po-and-pot-files),
+and a `Compiler` for converting [PO files](https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html)
+into a format that the runtime library ([angular-gettext](https://github.com/rubenv/angular-gettext))
+can consume.
+
+For more information, check out the [official website](https://angular-gettext.rocketeer.be).
+
+### `Extractor` options
+
+All `Extractor` options are optional.
+
+#### `startDelim`
+Delimiter that starts your Angular expressions. If you're using
+[custom delimiters](https://docs.angularjs.org/api/ng/provider/$interpolateProvider)
+for your Angular expressions, you should set the the `Extractor` can parse your
+expressions. Defaults to `{{`, which is Angular's default.
+
+#### `endDelim`
+Delimiter that ends your Angular expressions. Defaults to `}}`, which is
+Angular's default.
+
+#### `markerName`
+String to use as marker when parsing JavaScript for extractable strings.
+Defaults to `gettext`.
+
+#### `markerNames`
+Array of additional markers. If you're using a custom service that wraps
+`angular-gettext`, you'll probably want to pass the name of your service here
+so `angular-gettext-tools` can extract your strings.
+
+#### `lineNumbers`
+`false` to disable outputting line numbers in PO file references. Defaults to
+`true`.
+
+#### `extensions`
+Object mapping file extensions to extraction strategies. Valid
+strategies are `html` or `js`. For example, if you have a file `foo.bar` you
+want parsed as HTML, pass `{extensions: {foo: 'html'}}` to the `Extractor`.
+
+#### `postProcess`
+Callback to post process the resulting PO file. Passed a
+[`pofile`](https://www.npmjs.com/package/pofile) object.
+
+### `Compiler` options
+
+All `Compiler` options are optional.
+
+#### `format`
+Output format. `javascript` or `json`. Defaults to `javascript` for ease of use,
+but for more control over how strings are loaded into your app, consider using
+`json` and then generating your own JavaScript to suit your needs.
+
+#### `module`
+Name of the Angular module to output. Only used if `format` is `javascript`.
+Defaults to `gettext`.
+
+#### `requirejs`
+Whether to wrap the output in a [RequireJS](http://requirejs.org) module. Only
+used if `format` is `javascript`. Defaults to false.
 
 ## License 
 
     (The MIT License)
 
-    Copyright (C) 2013-2014 by Ruben Vermeersch <ruben@rocketeer.be>
+    Copyright (C) 2013-2015 by Ruben Vermeersch <ruben@rocketeer.be>
 
     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal