They use BFV, which is an FHE scheme allowing a limited number of fast additions and multiplications (enough for their use case). Zama uses TFHE, which allows

They use BFV, which is an FHE scheme allowing a limited number of fast additions and multiplications (enough for their use case). Zama uses TFHE, which allows any operation (eg comparisons) with unlimited depth. So if you only need add/mul, BFV, BGV and CKKS are good options. For anything else, you better use TFHE