Designers and checkers for the cloning methods you actually use at the bench.
Check homology arms and assemble multiple DNA fragments into one sequence.
Check 4 nt overhang compatibility and assemble Type IIs parts in one pot.
Design 15 bp homology arms and assemble fragments by homologous recombination.
Locate attB sites on vector and insert and generate the expression clone.
Plan Seamless Ligation Cloning Extract reactions with 25 bp homology arms.
Simulate TA and TOPO cloning of a PCR product into a linear vector.
Design primers for point mutations, insertions and deletions in one step.