diff --git a/pclpy/api.py b/pclpy/api.py
index f52c281..1d44801 100644
--- a/pclpy/api.py
+++ b/pclpy/api.py
@@ -9,6 +9,15 @@
 
 @register_point_cloud_function
 def extract_clusters(cloud, tolerance, min_size, max_size, merge_clusters=False):
+    """
+    Compute an EuclideanClusterExtraction on an input point cloud
+    :param cloud: input point cloud
+    :param tolerance: distance tolerance
+    :param min_size: minimum cluster size
+    :param max_size: maximum cluster size
+    :param merge_clusters: set to True to output a single cloud or False to output a pcl.vectors.PointIndices
+    :return: either an instance of pcl.PointCloud.* or pcl.vectors.PointIndices depending on merge_clusters
+    """
     pc_type = utils.get_point_cloud_type(cloud)
     ext = getattr(pcl.segmentation.EuclideanClusterExtraction, pc_type)()
     ext.setInputCloud(cloud)
@@ -37,6 +46,18 @@ def region_growing(cloud,
                    curvature_threshold,
                    residual_threshold
                    ):
+    """
+    Compute a region growing segmentation
+    :param cloud: input point cloud
+    :param normals: input normals (can be the same as input point cloud)
+    :param n_neighbours: number of neighbors to use
+    :param min_size: minimum cluster size
+    :param max_size: maximum cluster size
+    :param smooth_threshold: passed to setSmoothnessThreshold
+    :param curvature_threshold: passed to setCurvatureThreshold
+    :param residual_threshold: passed to setResidualThreshold
+    :return: a vector of pcl.PointIndices (pcl.vectors.PointIndices)
+    """
     pc_type = utils.get_point_cloud_type(cloud, normals)
     rg = getattr(pcl.segmentation.RegionGrowing, pc_type)()
 
@@ -63,6 +84,17 @@ def moving_least_squares(cloud,
                          polynomial_order=2,
                          num_threads=1,
                          ):
+    """
+    Compute a moving least squares on the input cloud
+    :param cloud: input point cloud
+    :param search_radius: radius search distance
+    :param output_cloud: optional point cloud to compute into
+    :param compute_normals: boolean, set to compute normals
+    :param polynomial_fit: boolean, set to compute using a polynomial function instead of a plane
+    :param polynomial_order: order of the polynomial function to fit
+    :param num_threads: optional number of threads to use
+    :return: a smoothed point cloud
+    """
     if output_cloud is None:
         if compute_normals:
             output_cloud = pcl.PointCloud.PointNormal()
@@ -92,6 +124,15 @@ def radius_outlier_removal(cloud,
                            negative=False,
                            indices=None,
                            ):
+    """
+    Compute a radius outlier removal
+    :param cloud: input point cloud
+    :param search_radius: radius search distance
+    :param min_neighbors: minimum number of neighbors
+    :param negative: passed to setNegative
+    :param indices: optional indices of the input cloud to use
+    :return:
+    """
     pc_type = utils.get_point_cloud_type(cloud)
     ror_filter = getattr(pcl.filters.RadiusOutlierRemoval, pc_type)()
     ror_filter.setInputCloud(cloud)
@@ -107,6 +148,16 @@ def radius_outlier_removal(cloud,
 
 @register_point_cloud_function
 def compute_normals(cloud, radius=None, k=None, indices=None, num_threads=1, output_cloud=None):
+    """
+    Compute normals for a point cloud
+    :param cloud: input point cloud
+    :param radius: radius search distance
+    :param k: use k nearest neighbors
+    :param indices: optional indices of the input cloud to use
+    :param num_threads: number of threads to do the computation
+    :param output_cloud: optional point cloud to compute the normals into
+    :return: a point cloud with normals
+    """
     if output_cloud is None:
         output_cloud = pcl.PointCloud.Normal()
     pc_type = utils.get_point_cloud_type(cloud, output_cloud)
@@ -129,6 +180,13 @@ def compute_normals(cloud, radius=None, k=None, indices=None, num_threads=1, out
 
 @register_point_cloud_function
 def octree_voxel_centroid(cloud, resolution, epsilon=None):
+    """
+    Subsample the input cloud to the octree's centroids
+    :param cloud: input point cloud
+    :param resolution: float size of the smallest leaf
+    :param epsilon: epsilon precision for nearest neighbor searches, passed to setEpsilon
+    :return: pcl.PointCloud.* same type as input
+    """
     pc_type = utils.get_point_cloud_type(cloud)
     vox = getattr(pcl.octree.OctreePointCloudVoxelCentroid, pc_type)(resolution)
     vox.setInputCloud(cloud)