The 22-year old is the latest new face Lee Bradbury has brought into Priory Lane, and the goalkeeper will be looking to fill the void left by previous stoppers Mark Smith and Sam Howes last term.
Hadler came through the youth system at EFL side Gillingham, turning professional in 2015.
He spent loan spells at non-league clubs Folkestone Invicta, Tonbridge Angels, Grays Athletic and Gloucester City over a two-year period, which also included a call-up to the England under-18 squad in the 2014 Victory Shield.
He became the Gills' second-choice goalkeeper in February 2018, before making his senior debut for Gillingham on 21 April 2018 in a 3–0 home defeat in the league against Blackpool where despite the scoreline, he was praised by then-boss Steve Lovell.
We welcome Tom to Priory Lane, and hope he enjoys his stay here at The Lane!