diff --git a/.babelrc b/.babelrc
index e68d2fea..f5277971 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,3 +1,3 @@
 {
-  "presets": ["es2015", "stage-2", "react"]
+  "presets": ["es2015", "stage-2", "react", "flow"]
 }
diff --git a/package.json b/package.json
index 7d107006..5f3130b2 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "babel-preset-stage-2": "6.24.1",
     "babel-polyfill": "6.26.0",
     "babel-preset-react": "6.24.1",
+    "babel-preset-flow": "6.23.0",
 
     "css-loader": "0.28.7",
     "less-loader": "4.0.5",
diff --git a/web/app/brep/geom/curves/parametricCurve.js b/web/app/brep/geom/curves/parametricCurve.js
index bc5ed833..3c86fea9 100644
--- a/web/app/brep/geom/curves/parametricCurve.js
+++ b/web/app/brep/geom/curves/parametricCurve.js
@@ -1,24 +1,24 @@
+// @flow
+interface ParametricCurve {
 
-export default class ParametricCurve {
+  domain(): number[];
 
-  domain() { }
+  degree(): number;
+  
+  degree1Tess(): number[][];
 
-  degree() { }
+  eval(u: number, num: number): number[];  
 
-  degree1Tess() {}
+  point(param: number): number[]; 
 
-  eval(u, num) { }
+  param(point: number[]): number;
 
-  point(param) { }
+  transform(tr); 
 
-  param(point) { }
+  optimalSplits(): number;
 
-  transform(tr) { }
+  normalizeParametrization();
 
-  optimalSplits() { }
-
-  normalizeParametrization() { }
-
-  invert() { }
+  invert();
 }