I remember dealing with a large credential stuffing attack at a marketplace right after we announced our series B ~2018. We developed some tools to keep them out through pattern matching, but it was not easy and it took some time to develop those tools.
Best companies to work with were spycloud.com and sift.com.
spycloud actually specializes in identifying leaked credentials, which are what attackers use in the credential stuffing list they go through, so you could identify "stuffable" credentials prior to the attack happening, which is nice.
sift was great at helping to just identify fraud in general, so if an account did quietly get compromised, we could identify it before the transaction was finalized.
Best companies to work with were spycloud.com and sift.com.
spycloud actually specializes in identifying leaked credentials, which are what attackers use in the credential stuffing list they go through, so you could identify "stuffable" credentials prior to the attack happening, which is nice.
sift was great at helping to just identify fraud in general, so if an account did quietly get compromised, we could identify it before the transaction was finalized.