What stack is this site running?
Find technologies, catalog signals, and changes. Export lead lists. Plug into your workflows.
Segments, feeds, exports, API + MCP — built for growth operators.
Trusted by growth teams at
Turn stacks into segments
Everything you need to find, filter, and export web signals for outbound.
Lookup
Enter a domain → get detected technologies, signals, and evidence. Instant results.
Segments
Save definitions for lead lists. Example: 'Shopify stores with 1k+ products and no Klaviyo.'
Feeds
Track what changed over time. Example: 'New Meta Pixel installs last 30 days.'
Exports
CSV and Parquet. Scheduled drops. Take your data where you need it.
API + MCP
Integrate into Clay, n8n, Zapier, internal pipelines. Agent-native workflows.
Reason Codes
Every lead includes the 'why.' Evidence-backed signals for confident outreach.
Built for growth operators
Stack signals power every stage of your outbound motion.
Lead Generation
Build lists by stack + intent. Find 'ready for pitch' targets fast.
Market Research
Compare market shares and technology trends across verticals.
Competitor Analysis
Discover who uses competitors' software. Track migration patterns.
Data Enrichment
Technology, company, and catalog signals. Join onto your existing datasets.
Security Recon
Reveal web technologies and version numbers for security assessments.
Why What-Stack?
We're not another tech lookup. We're a web signal warehouse.
Domains tracked
Technologies detected
Monthly crawl updates
API response time
Find. Filter. Export. Ship.
Start building your first segment in minutes. No credit card required.