Quick answer: Greenhouse, Lever, and Ashby each publish a public job-board API that any job aggregator can hit — no auth required. An ATS tech stack detector calls those APIs, strips the HTML from each job description, then runs a curated vocabulary of ~110 canonical tech names against the text to produce a deduplicated detected_techs list per job row. The Apify Actor below does it for $0.005 per row ($5.05 per 1,000 jobs, including the one-time $0.05 start fee), with exponential backoff, per-company fault isolation, and Pydantic-validated output ready to drop into any CRM pipeline.
Every B2B sales motion eventually hits the same wall: you need to know what your prospect actually runs in production, and front-end sniffers like BuiltWith and Wappalyzer can't tell you. They read Cloudflare headers, tag-manager IDs, and JS bundle manifests — which surfaces HubSpot and Segment beautifully but says nothing about whether the company runs Postgres or Snowflake, Kafka or RabbitMQ, Kubernetes or Nomad. Engineering teams declare their real stack in job descriptions. A "Senior Backend Engineer" posting that lists Django, Postgres, Kafka, and Kubernetes tells you more about their infrastructure than any front-end scan ever will.
