crt.sh vs SurfaceDiff: Side-by-Side Comparison (2026)

crt.sh: Bash script for subdomain enumeration via crt.sh certificate transparency logs. Core capabilities include Subdomain enumeration via certificate transparency logs, Automated querying of crt.sh website, Parsing and filtering of crt.sh output..

SurfaceDiff: Continuous external attack surface monitoring that shows what changed between scans. built by SurfaceDiff. Core capabilities include Domain baseline scan for publicly exposed assets, Subdomain discovery, DNS record enumeration..

Both serve the External Attack Surface Management market but differ in approach, feature depth, and target audience.

crt.sh differentiates with Subdomain enumeration via certificate transparency logs, Automated querying of crt.sh website, Parsing and filtering of crt.sh output. SurfaceDiff differentiates with Domain baseline scan for publicly exposed assets, Subdomain discovery, DNS record enumeration.

crt.sh and SurfaceDiff serve similar External Attack Surface Management use cases: both are External Attack Surface Management tools, both cover DNS Security, Subdomain Enumeration, Security Scanning. Key differences: crt.sh is Free while SurfaceDiff is Commercial. Review the feature comparison above to determine which fits your requirements.