Programmatic OSINT Sources
The idea: an identifier (email · name · domain · username · phone · company · IP) keys into a rich, machine-readable response. This skill is a curated, verified catalog of sources where that pull is low-lift — a plain URL, a keyless API, or a real free-tier key — so an agent can script it. It generalizes the Gravatar "email → profile" trick out to breach data, infrastructure, code repos, public records, presence oracles, phones, and more.
This is the broad source catalog. For the email-specific workflow (DNS/MX, theHarvester, holehe, GHunt, SMTP/people-API verification, Gravatar/Libravatar/unavatar) see the sibling skill domain-email-enumeration. This skill covers everything outside that email-and-avatar core.
How to use this skill
Start from the identifier you already have. The catalog is organized so you can jump to "I have an X, I want a Y":
I have… I want… Go to email is it breached? / infostealer exposure breach-and-exposure email the person behind it (name/role/socials) contact-enrichment · presence-oracles name + company/domain a verified work email contact-enrichment domain subdomains, hosts, tech, related infra infrastructure-recon domain / company officers, owners, filings, litigation public-records company name canonical domain + firmographics + IDs contact-enrichment · market-signals company hiring intent, tech stack, ad/news signal market-signals username / handle linked accounts, real name, activity presence-oracles · developer-identity name / org / email public code commits → real emails developer-identity phone number carrier, line type, name, platform footprint phone-and-messaging IP ports, CVEs, co-hosted domains, ASN/abuse contact infrastructure-recon Prefer keyless → free-key → cheap-paid, in that order. Every entry is tagged. Reach for a paid tier only when a keyless one can't answer.
Chain sources into a waterfall. e.g. company name → canonical domain (Clearbit autocomplete) → subdomains (Cert Spotter) → contributor emails (GitHub) → verify (Abstract) → enrich the person (People Data Labs) → confirm they're active (Duolingo/Keybase). The reference files note what feeds what.
Re-verify before you rely on it. These endpoints churn — free tiers shrink, hosts move, ToS changes. Freshness/confidence caveats are on every entry; treat pricing and free-quota numbers as "last-checked, re-check now."
Highest-value keyless sources (zero auth, start here)
The fastest wins — no signup, scriptable in one curl. Full details + more in the reference files.
| Source | Identifier → data | Category |
|---|---|---|
| Hudson Rock Cavalier | email/domain → infostealer-infection exposure | breach |
| XposedOrNot | email → breaches + risk score | breach |
| LeakCheck (public) | email/username/phone → breach source names + PII categories | breach |
| crt.sh / Cert Spotter | domain → subdomains (from CT logs) | infra |
| Shodan InternetDB | IP → ports, CVEs, hostnames | infra |
| RDAP (rdap.org) | domain/IP/ASN → registrar, dates, nameservers, ownership | infra |
| HackerTarget | domain ↔ subdomains / reverse-IP | infra |
| RIPEstat | IP/ASN/prefix → whois, abuse contact, routing, geo | infra |
| Common Crawl index | domain → web-scale URL/subdomain list + page text | infra |
| GitHub commit/patch | name/org/email ↔ username + real commit emails | dev |
| Sourcegraph | email/name → wherever it appears across public code | dev |
| Wikidata | company/person → cross-linked external IDs (LinkedIn/GitHub/ORCID/SEC…) | contact |
| ORCID / OpenAlex | name/email → researcher affiliation, works, co-authors | contact |
| Clearbit autocomplete | company name → canonical domain | contact |
Hunter email-count |
domain → # emails by department + seniority | contact |
| GLEIF | company → legal entity + who-owns-whom | records |
| OpenFEC | donor name/employer → name+address+employer+occupation | records |
| Duolingo users API | email → real name + username + avatar | presence |
| Keybase | username → cryptographically-linked accounts + PGP | presence |
| Greenhouse / Lever / Ashby | company → all open roles (tech stack + hiring intent) | signals |
| X syndication API | tweet id → author profile (no auth) | phone/msg |
Reference catalog
Load the file for the category you need — see references/INDEX.md for the map.
- breach-and-exposure.md — credential leaks, infostealer exposure, paste/darkweb archives.
- infrastructure-recon.md — certificate transparency, internet-scan engines, DNS/RDAP/WHOIS, passive DNS, ASN/abuse contacts, web-index/history.
- developer-identity.md — GitHub/GitLab/npm/PyPI/Sourcegraph/GH-Archive: code repos as an email↔identity graph.
- contact-enrichment.md — B2B email finders, email validation, firmographic resolvers, knowledge graphs (Wikidata), academic identity (ORCID/OpenAlex).
- public-records.md — government/legal/financial registries: officers, beneficial owners, donors, filings, litigation, procurement.
- presence-oracles.md — identifier → "real person + profile" existence checks across consumer platforms (the direct generalization of the Gravatar trick).
- phone-and-messaging.md — phone → carrier/line-type/name, and messaging-app footprint (Telegram/Discord/X/WhatsApp/Signal).
- market-signals.md — hiring signals (job boards), news (GDELT), ad transparency, maps/reviews, tech-fingerprint.
- connectors.md — how to get this data via Claude connectors / MCP servers instead of raw
curl, prioritized free / no-account / low-lift (what's already connected, 1-click directory options, remote-URL MCPs, and self-host power tools).
Legal, ToS & ethics (read before scripting)
This skill is for authorized work: B2B prospecting on business contacts, defensive security / threat intelligence, due diligence, and competitive research. With that scope:
- Respect each source's ToS and rate limits. Many keyless endpoints (Duolingo, X syndication,
Truecaller, LinkedIn Voyager, WhatsApp self-sessions) are undocumented or explicitly forbid
automation. They're fine for low-volume investigative pivots; they are not for bulk
scraping, and some carry account-ban or legal risk (LinkedIn
hiQ, Truecaller). Each entry flags this — heed it. - Breach / infostealer / credential data is defensive. Hudson Rock, HIBP, DeHashed, ProxyNova COMB, Intelligence X etc. exist for exposure assessment and threat intel. Use them to protect a domain you're authorized on or assess a counterparty's risk — never to obtain or use others' credentials. Treat any returned plaintext as toxic.
- Handle PII responsibly. Much of this is personal data (home addresses in FEC/registry data, phone→name, breach records). Collect only what the task needs, store it as your engagement's rules require, and honor GDPR/CCPA where they apply.
- No secrets in the repo. Every example uses a
$ENV_VARor placeholder key. Never commit a real key, token, or cookie.
If a task would use these sources to target a private individual rather than a business context, or in a way the user wouldn't expect, stop and confirm scope first.
Related skills
- domain-email-enumeration — the email/avatar core (theHarvester, holehe, GHunt, SMTP/people-API verification, Gravatar).
- client-discovery-osint · intelligence-dossier · verification-audit · company-legal-reputation-research — workflows that consume these sources.
- website-techstack-analysis · google-dorking-osint — adjacent recon techniques.
Freshness: catalog compiled 2026-07; API availability, free tiers, and pricing change frequently. Re-check any endpoint before depending on it, and downgrade your confidence for entries tagged
[shaky].