Is it easy to replace the timing belt tensioner, or do i need any special tools.
fiat bravo 1.4 16 valve 2007.

According to eLearn you do need a special tool to turn the tensioner.
You also need to know the procedure from elearn in order to ensure the correct tension after the correct number of engine turns.
Use eLearn to familiarize yourself wit the procedure and the tools.

I wold not attempt it without all the timing tools at hand, just in case you screw up the timing then you could just reset it.

Also if it were me i would also replace the belt. (maybe the water pump if it's been a while since last replaced)

The kit you will need (it's for the 1.2 16 v but also works on the 1.4:
https://www.aliexpress.com/item/Engine-Timing-Kit-Set-Tool-1-2-16V-twin-cam-petrol-engine-For-Fiat-PUNTO-BRAVA/32302916767.html?spm=2114.01010208.3.1.TX4VXe&ws_ab_test=searchweb201556_0,searchweb201602_4_10057_10056_10065_10037_10068_10055_10054_10069_10059_10033_10058_10032_418_10073_10017_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_7&btsid=d741f949-21c4-4b45-9be6-896519dfe85d

You also need various other tools like a set of sokets, a special tool for loosening up the cam sproket, a torque wrench(for retightening the cam sproket), a good way of supporting the engine while the engine mount and wheel are off.

Just pay someone for the job unless you can borrow the tools and have someone helping you that has done timing belts in the past .

Hi
I changed my timing belt, tensioner and water pump this summer whitout using any special tools. But I do think it would have been easier if I had them. This was on a mjt 120hp 8v..

/Thomas