diff --git a/readme.md b/readme.md
index e896538..8d0bad8 100644
--- a/readme.md
+++ b/readme.md
@@ -23,6 +23,8 @@ Inspired by the [awesome](https://github.com/sindresorhus/awesome) list thing.
 - [Date](#date)
 - [Image](#image)
 - [Text](#text)
+- [Math](#math)
+- [Data validation](#data-validation)
 - [Parsing](#parsing)
 - [Humanize](#humanize)
 - [Compression](#compression)
@@ -196,6 +198,11 @@ Inspired by the [awesome](https://github.com/sindresorhus/awesome) list thing.
 - [mathjs](https://github.com/josdejong/mathjs) - An extensive math library for JavaScript and Node.js.
 
 
+### Data validation
+
+- [joi](https://github.com/spumko/joi) - Object schema description language and validator for JavaScript objects.
+
+
 ### Parsing
 
 - [css](https://github.com/reworkcss/css) - CSS parser / stringifier.