align two sequences.

Paste two protein or nucleotide sequences. SeqAlign runs the exact dynamic-programming alignment — Needleman-Wunsch for global, end-to-end alignment, or Smith-Waterman for the best local sub-segment — scored with the real BLOSUM62 substitution matrix (proteins) or an identity matrix (nucleotides) and a linear gap penalty. You get the aligned strings, the optimal score, match/mismatch/gap counts, and percent identity. No heuristic, no GPU — the true optimum.