Prospecting Data Sources

Tool selection guide for prospecting across all three branches.

Tool selection by goal

Apollo

Use for: General B2B / SaaS firmographic + contact data. Best starting point if you don't already have a list.

Strengths:

• Large database (>200M contacts, >60M companies)
• Strong filtering UI (industry, size, technologies, signals)
• Integrated email + LinkedIn finder
• Pay-as-you-go and tiered plans

Watch out for:

• Data freshness varies — re-verify before scoring as "Hot"
• Email accuracy ~60–80% — always validate
• Bulk export limits apply

Integration: see apollo.md

Clay

Use for: Multi-source enrichment, waterfall lookups, custom scoring logic. When list quality matters more than list size.

Strengths:

• Waterfall logic: query providers in order and stop at the first verified result (see sourcing-and-enrichment.md for ordering and the bake-off)
• 100+ data provider integrations
• AI-powered enrichment (LLM-driven extraction from URLs)
• Custom columns + scoring formulas
• Native MCP server

Watch out for:

• Per-credit pricing can spike on large lists
• Complexity overhead — easy to over-engineer workflows

Integration: see clay.md

ZoomInfo

Use for: Enterprise B2B + intent data. Mid-market+ buyer profiles.

Strengths:

• Enterprise-grade firmographic depth
• Intent signals (companies searching topics relevant to your offer)
• Best-in-class for >$50K ACV B2B sales
• Native MCP server

Watch out for:

• Expensive ($15K+/yr starter)
• Overkill for SMB prospecting
• Locked into multi-year contracts typically

Integration: see zoominfo.md

Waterfall aggregators (FullEnrich, LeadMagic)

Use for: Email and phone enrichment through one API call that queries several providers in sequence. The simpler alternative to building a waterfall in Clay.

Watch out for:

• Coverage and false-positive rates vary by ICP; run the bake-off in sourcing-and-enrichment.md before committing
• Verify results anyway; finding an address isn't the same as confirming it

Integration: see fullenrich.md and leadmagic.md

Clearbit (legacy)

Clearbit was absorbed into HubSpot (Breeze Intelligence). Its free tools ended in 2025, and new standalone API access is no longer generally available. Use HubSpot's enrichment if you're on HubSpot; otherwise use the providers above.

Integration: see clearbit.md

Hunter / Snov

Use for: Email pattern discovery + lightweight verification on small lists.

Hunter strengths:

• Domain-based email discovery
• Built-in deliverability verification
• Free tier reasonable for occasional use

Snov strengths:

• Email finder + drip campaigns (overlap with outreach tooling)
• Bulk verification
• Cheaper than Hunter at scale

Watch out for:

• Both are pattern-guessing tools — accuracy depends on the target company's email pattern being inferable
• Always run results through a dedicated validator (Truelist or similar) before outreach

Integrations: see hunter.md, snov.md

Truelist

Use for: Email deliverability validation before adding contacts to outreach lists. Critical safety step.

Strengths:

• Single-email sync verification (/api/v1/verify_inline) + bulk async (/api/v1/verify)
• Returns email_state (ok / email_invalid / risky / unknown / accept_all) + email_sub_state (email_ok / is_disposable / is_role / unknown_error / failed_smtp_check) + did-you-mean typo suggestions
• Catches catch-all domains, role accounts, spam traps, disposable providers
• Official MCP server for agent-driven workflows (Claude, Cursor, VS Code)
• Official SDKs in 7 languages + framework integrations (Django, Laravel, Next.js, Rails, React, Svelte, Vue, WordPress)
• Native integrations with Mailchimp, Klaviyo, HubSpot, Zapier, Make, n8n, Clay, Salesforce, more
• Pay-per-email pricing

Why this matters: Cold email reputation craters when bounce rates exceed 2%. Validating before sending is non-negotiable. Apollo/ZoomInfo/Hunter data is often 60–80% accurate — Truelist catches the rest.

Integration: see truelist.md

LinkedIn Sales Navigator

Use for: Manual decision-maker discovery. The gold standard for B2B / SaaS prospecting but only when used as a research tool.

Strengths:

• Most accurate decision-maker data in the industry
• Real-time job changes, posts, signals
• Lead lists, alerts, saved searches
• Inmail credits (separate channel from cold email)

Hard rules:

• Never bulk scrape. LinkedIn aggressively bans scrapers. Account ban risk is real and permanent.
• Use Sales Nav as a research interface — open profiles, read, take notes, capture key data manually.
• Apollo and other tools claim LinkedIn data via partnerships / public mirroring — verify the source legitimacy before assuming compliance.

Integration: no MCP or API access at consumer level. Manual research only.

BuiltWith / Wappalyzer

Use for: Tech stack qualification (SaaS branch).

BuiltWith:

• ~50K+ technologies tracked
• API + bulk lookups (paid)
• Historical data (when stack changed)

Wappalyzer:

• Free browser extension; paid API
• Lighter coverage than BuiltWith
• Faster for one-off lookups

Cross-reference both for high-confidence tech stack signals.

Crunchbase

Use for: Funding signals (SaaS branch).

Strengths:

• Free tier shows recent funding events
• Paid (Pro / Enterprise) unlocks alerts and deep history
• API access for paid users

Watch out for:

• Coverage is best for VC-backed companies; bootstrapped + small businesses underrepresented
• Self-reported data — verify funding amounts independently

GitHub (stargazers / forks / watchers)

Use for: Developer-intent prospecting. Especially powerful for dev-tool SaaS — stargazers of competitor or category-defining repos are in-market signal.

Strengths:

• Public API, no scraping concerns
• High signal quality (a starred repo = explicit interest)
• Forks are an even stronger signal (intent to modify, not just bookmark)
• Bundled github-prospects.js CLI handles pagination + enrichment + CSV output
• Free with 5,000 req/hr authenticated rate limit

Watch out for:

• Only ~5–20% of users publish email — pair with Apollo/Clay/Hunter for enrichment
• Very-popular repos (100K+ stars) are mostly noise; smaller targeted repos (5K–25K) give better signal density
• Most prospects are individuals, not company contacts directly — need to figure out their company from company field or LinkedIn

Integration: see github.md

Firecrawl / Browserbase (single-target site research)

Use for: Programmatically extracting content from a prospect's own website that you already found via discovery on platforms like Google Maps, Yelp, or LinkedIn. Not for scraping those platforms themselves.

Firecrawl

• Best for: "Just give me the page as markdown" — Local SMB website status checks, B2B company about/team page extraction, structured field extraction
• Strengths: Low overhead, returns clean LLM-ready markdown, handles most JS-rendered sites, has an MCP server
• API + MCP + SDKs: Node, Python, Go, Rust

Browserbase

• Best for: When you need real Chromium — JS-heavy pages, cookie consent dialogs, form submission to reach a contact page, session state
• Strengths: Full browser control via Playwright/Puppeteer; Stagehand provides AI-friendly natural-language extraction; session recordings for debugging
• API + MCP (Stagehand) + SDKs: Node, Python

Critical compliance line

Both tools can technically point at any URL. The hard rule:

• ✓ OK: extracting content from a single business's own website (joescoffeeshop.com) that you found through manual discovery
• ✗ NOT OK: pointing them at google.com/maps, LinkedIn search results, Yelp listings, or any platform whose ToS prohibits bulk extraction

Discovery happens on platforms (manual browser-assisted research). Extraction happens on individual public business sites.

Integrations: see firecrawl.md, browserbase.md

Visitor identification (RB2B, Warmly, Vector)

Use for: Identifying anonymous site visitors as warm intent signals.

Strengths:

• Pixel-based visitor → company identification
• High-intent: they came to your site, they're already in research mode
• Slack / email alerts on key visits

Watch out for:

• Privacy/GDPR considerations — verify your privacy policy disclosures
• Person-level identification raises higher concerns than company-level

Integration: see rb2b.md

Built into a site platform (Ploy ◆)

Some site platforms identify visitors natively. Ploy, a Verified Partner of this repository (disclosure, not endorsement), returns person, company, title, and pages viewed for visitors to sites hosted on it, with contact enrichment alongside.

Watch out for:

• Only works if the site is hosted on Ploy; for any other site use a pixel tool like RB2B, Warmly, or Vector
• Metered by plan (as of 2026-10: 50 enrichments a month on Starter, 1,000 on Pro)
• Ploy says no consent banner is needed; the same privacy and person-level cautions as above still apply, and the legal call is yours

Integration: see ploy.md

Free / browser-only fallbacks

When the user has no paid tools, lean on:

• Google Search — exact business name + city + role searches
• LinkedIn (manual, no scraping) — company pages, employee lookups
• Crunchbase free tier — funding events
• Wappalyzer browser extension — tech stack at a glance
• Hunter.io free tier — 25 lookups/month
• Google Maps — for Local SMB discovery
• Business websites + About pages — primary source for any claim
• News sites + press releases — trigger event monitoring via Google Alerts

Slower than tooled-up workflows, but produces high-quality smaller lists if the user is willing to do the work.

Sequencing recommendations

A typical full-stack prospecting workflow:

1. Define ICP from product-marketing context (no tools needed)
2. Initial list from Apollo or ZoomInfo (firmographic filter)
3. Enrich with Clay (waterfall: tech stack, funding, trigger events)
4. Decision-maker mapping in LinkedIn Sales Nav (manual)
5. Email pattern discovery with Hunter or Apollo's built-in
6. Email validation with Truelist before final list
7. Hand off to cold-email skill for outreach copy

Adapt this sequence based on which tools the user actually has.