diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f52c44ec..1fcd19b9 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -37,7 +37,7 @@ Once you finish this, you will have the project exposed in ports `8000` through
 
 ## Project tests
 
-In order to ensure stability and no regressions are introduced while developing new features, this project has three types of tests.
+In order to ensure stability and no regressions are introduced while developing new features, this project has different types of tests.
 
 * **Unit tests**: These are the simplest to run, and usually test individual pieces of code, replacing any external dependency by mocks.
 
@@ -53,6 +53,8 @@ In order to ensure stability and no regressions are introduced while developing
 
     These are the best tests to catch regressions, and to verify everything interacts as expected.
 
+    They use MySQL as the database engine, and include some fixtures that ensure the same data exists at the beginning of the execution.
+
 * **CLI tests**: *TBD. Once included, its purpose will be the same as API tests, but running through the command line*
 
 Depending on the kind of contribution, maybe not all kinds of tests are needed, but the more you provide, the better.