59 Public Databases for B2B Prospecting (Free, Scored, Signal-Ready)

Most cold email fails because the list is garbage. Not the copy. Not the offer. The list.

You are sending "I noticed you are growing fast" to a company you found on ZoomInfo with no idea if they are actually growing, struggling, hiring, exiting, or winning a government contract.

The signal is everything. Here are 59 public databases, what data each one holds, and the exact signal each gives you for situation-based outreach that lands.

Government APIs (Free, No Auth)

The most underused data category in B2B sales. Federal and state governments publish enormous datasets that most sales teams have never heard of. All of the following are free, legal, and require no authentication.

NPI Registry

Every licensed healthcare provider in the US. Free API, no key required.

The signal: NPI type tells you if it is a solo practitioner or a group practice. Taxonomy code tells you the specialty. Cross-reference organizational NPI count in a geography to find independent practices before roll-ups absorb them. That window closes fast.

EPA FRS and ECHO

Industrial facilities filtered by NAICS code and state. Returns JSON with no key required.

The signal: If a company is in the EPA Facility Registry, they operate at industrial scale. ECHO adds compliance history. A facility with open violations is a company with active operational pain. Pair with OSHA data and you know how much of their time goes to regulatory headaches.

FDA Establishment Registration

All food, drug, device, and cosmetic manufacturers. Annual bulk download, free.

The signal: Registration type tells you what they make. A company registered as both a food manufacturer and a contract packager has two business lines and two angles. New registrations in the last 12 months mean they just started manufacturing and have not figured out their systems yet.

USASpending.gov

Federal contract awards with full vendor details. Free API, no auth.

The signal: Award totals by year are a revenue floor, not a ceiling. A company pulling $8M from federal contracts probably has $25M or more in total revenue. Renewal dates are in the data. A contract expiring in six months means they are entering procurement mode. The awarding agency tells you their biggest customer relationship.

SEC EDGAR

Public companies and private Reg D filers. Free API.

The signal: Private companies raising capital file Reg D. You can find VC-backed companies before they hit Crunchbase. SIC codes for filtering. Annual 10-K filers have revenue in the filing if you want to pull it.

SAM.gov

Federal contractor registry. Free API key, instant access, no approval process.

The signal: Self-certified size classifications (8a, HUBZone, WOSB, SDVOSB) tell you the founder profile. These companies have specific compliance headaches tied to their certifications that most vendors completely ignore. That is an angle nobody else is using.

FMCSA SAFER

3.8 million trucking and freight carriers. Bulk download available at no cost.

The signal: Vehicle count is the number everyone misses. 25 or more power units means a company doing $10M or more in freight revenue. 100 or more means a regional carrier with completely different operational complexity. Safety rating (Satisfactory, Conditional, Unsatisfactory) tells you if they have active DOT compliance risk. Conditional rating means liability on the radar and leadership under pressure.

DOL OFCCP Federal Contractor List

Companies with federal contracts above the $50k AAP threshold.

The signal: Strong indicator for professional services, defense, and IT companies. These companies have compliance requirements tied to their contracts. That is a specific pain point most vendors ignore.

Trade and Industry Sources

ENR Top Lists

Construction contractors with confirmed reported revenue. Free Excel download.

The signal: This is the only free source where construction revenue is verified, not estimated. The list segments by specialty (general, specialty contractor, subcontractor) which tells you the business model. A Top 400 Contractor at $80M does completely different work than a Top 100 Specialty Contractor at $80M. Revenue by segment is in the data.

OSHA Enforcement Data

Bulk CSV download, no auth required. Covers every OSHA inspection and citation.

The signal: Violation type matters more than violation count. Repeat violations mean they know about the problem and have not fixed it. Either they cannot afford to or leadership does not prioritize safety. Recent inspection plus citation is an active regulatory moment. Naturally biased toward construction, manufacturing, and warehousing.

Thomasnet

Industrial supplier and manufacturer directory.

The signal: The capabilities list tells you more than NAICS codes. A company listed as "precision CNC machining, aerospace-grade aluminum, AS9100 certified" has specific customer requirements that a job shop does not. Certifications in their profile mean they sell to customers who require them. That is a completely different conversation.

Certifications and Accreditations

B Corp Directory

8,000 certified companies globally. Public and scrapeable.

The signal: B Corp certification requires renewal every three years. Companies approaching their renewal window are actively thinking about impact measurement. That is a real moment for anything touching operations, HR, supply chain, or ESG reporting.

FTC FDD Database

Franchise Disclosure Documents are public PDFs. Exhibit C lists every franchisee by state.

The signal: Multi-unit operators with five or more locations are running a small business empire. They have the HR complexity of a 50-person company and the systems sophistication of a 10-person company. That gap is the pitch. Single-unit is a lifestyle business. Multi-unit is a scalability problem.

ISO Certified Companies (IAF CertSearch)

Global database of ISO-certified companies. Free search at iafcertsearch.org.

The signal: ISO 9001 is quality management. ISO 14001 is environmental. ISO 45001 is occupational health and safety. A company certified in all three is playing enterprise supplier. Their certification is a selling point to their customers, which means losing it is a real risk.

FDA Establishment Registration (Second Pass)

New registrations in the last 12 months deserve their own filter.

The signal: Companies that just started manufacturing under FDA oversight are figuring it out. They do not have systems yet. That is a specific moment you can walk into before they have chosen their vendors.

Events and Trade Shows

Map Your Show

Exhibitor data for hundreds of trade shows. Consistent URL patterns across all events.

The signal: They paid to exhibit. Booth cost at a mid-tier trade show starts at $5,000 to $15,000 and runs to $100,000 or more for large booths. That is active pipeline investment. A company in selling mode. Floor map position relative to competitors tells you relative spend and confidence level.

Conference Sponsor Pages

Individual conference websites, scrapeable.

The signal: Sponsorship tier is a budget signal. A company sponsoring at Gold level while their competitors are at Bronze is outspending the category. That is ambition, a new market bet, or a defensive response. Any of those is a conversation starter.

Capital and Startup Data

YC Alumni

Full company list with batch, status, and description. Unofficial JSON API available.

The signal: Batch year tells you the growth stage. YC W2021 companies are four years old now. Past the initial sprint, hitting scale complexity. YC W2023 is still finding product-market fit. Same source, completely different outreach angle. Active status filter removes dead companies automatically.

Inc. 5000

Fastest-growing private companies with verified revenue and three-year growth rate. Free and scrapeable.

The signal: Growth rate is more useful than revenue. A company growing 300% over three years at $15M revenue has completely different pain than one growing 40% at $80M. The fast grower has outgrown their systems. The slower larger company has optimization problems. Filter by growth rate, not just size.

Crunchbase (via Apify)

VC-backed company data. Direct API requires subscription. Apify actor is the practical path.

The signal: Last funding round date plus round size tells you the cash position. A company 18 months post Series A is approaching their next fundraise or profitability push. That is a 24-month clock. Series B companies are scaling sales. They need pipeline infrastructure. Seed stage companies need things to work before they can raise.

Deloitte Technology Fast 500

Fast-growing tech, media, and telecom companies. Free download.

The signal: Cross-reference with Inc. 5000. Companies on both lists are verified fast-growers with two independent datasets confirming the growth. Higher confidence than one list alone.

Specialty and Professional Directories

Repvue

Tech sales org data including quota attainment percentages. Public company profiles.

Quota attainment under 60% is one of the most valuable free signals in B2B sales. It means more than half the sales team is missing their number. Leadership is under pressure and actively looking for answers. Most sellers have never heard of this source.

The signal: Ramp time data tells you if the problem is hiring the wrong people or failing to onboard them. Two completely different conversations. Two completely different offers.

Clutch

B2B agency directory with client reviews. Apify actor available.

The signal: The reviews are the real data, not the listings. Clients describe the problems they had before hiring the agency. "We needed someone to fix our broken outbound" is a pain statement in the wild. Minimum project size tells you the revenue band. Mine the reviews, not the profile pages.

State Contractor License Boards

Trade licenses by state. FL DBPR covers HVAC, electrical, plumbing, and contractor in one portal.

The signal: License class tells you the scale. An unlimited general contractor license means no project size cap. A Class B license has a ceiling. License age tells you years in business. Active vs. inactive tells you if they are still operating.

Tech and Product Intelligence

G2 and Capterra Reviewers

Software review site data. Apify actors available for both.

The signal most people miss: it is not the vendor data that is valuable. It is the reviewers. A VP of Sales who wrote a Salesforce review six months ago and a HubSpot review three months ago is mid-migration. A company whose employees are actively writing reviews for software in a category is evaluating, switching, or recently adopted. That is a buyer in motion.

BuiltWith and Wappalyzer

Tech stack per domain. Clay integration available. Bulk access requires subscription.

The signal: Combinations matter more than individual tools. Shopify plus Klaviyo plus Recharge means subscription commerce. Shopify with no email platform means an untapped opportunity. You are not looking for one tool. You are looking for tool patterns that map to specific pain.

Product Hunt

Startup product launches with upvote counts. Unofficial API available.

The signal: Upvotes tell you if anyone cares. 500 or more on launch day means traction. 50 means still finding product-market fit. Maker profile links back to the founder. The launch description tells you the exact problem they claim to solve, which is the exact conversation you can walk into.

Listen Notes

Podcast guest data with episode context. Free API with limited tier.

The signal: A founder who appears on five industry podcasts in six months is in a visibility campaign. They are pitching. They are building pipeline. The episode topics tell you what problems they talk about publicly. That is your in.

How to Actually Use This for Cold Email

The mistake is treating these as list sources.

They are signal sources. Build your base list from LinkedIn, lookalike discovery, or Google Maps. Then enrich it with signals from these databases.

• FMCSA SAFER enrichment tells you the fleet size. That changes the opening line.
• Repvue enrichment on a tech company tells you if the sales team is struggling. That changes the offer.
• YC batch plus funding date tells you the growth stage. That changes the urgency framing.
• BizBuySell overlay tells you if they are listed for sale. That changes everything.

The companies pulling exclusively from ZoomInfo are writing the same generic emails to the same generic lists.

The ones cross-referencing public databases with behavioral signals are writing emails that read like they already know you.

That is the gap. Not technology. Data discipline.

Accessibility Scores for All 59 Sources

We scored every source on a 1 to 5 scale:

• Score 5: Free API or bulk download, company-level data, no auth
• Score 4: Scrapeable, no login, useful fields
• Score 3: Searchable web UI only, no bulk export
• Score 2: Login required for useful data
• Score 1: Enterprise subscription or fully gated

Most of the best signal sources are 4 or 5. The ones rated 1 or 2 (STR, Datassential, BuiltWith bulk) have better free alternatives for most ICPs.