A device (1) for static mixing and heat exchange comprises a cladding element (2) and a mixer insert (3), whereby the mixer insert (3) is in the operative state arranged inside the cladding element (2). The mixer insert has a longitudinal axis and comprises a first group (5) of web elements and a second group (6) of web elements. The first group (5) of web elements extends along a first common group plane (7) and the second group (6) of web elements extends along a second common group plane (8). At least a portion of the web elements (9, 10) is provided with channels (11, 12). The channels extend from a first end (13) of the web element (11) to a second end (14) of the web element (11). The cladding element (2) comprises a corresponding channel, which is in fluid connection with the first end (13) and the second end (14) of the web element whereby the transition from at least one of the first (13) and second ends (14) of the web element to the corresponding channel in the cladding element (2) is free from gaps.