Domain to Company API: Turn a Website Into a Company Record

A domain to company API takes a website domain such as example.com and returns the business behind it: name, industry, size band, location and contact basics. It does not guess when it lacks data. A good one returns an explicit not-found result so your system can treat the domain as unknown.

What “domain to company” really means

A domain is a label, not a company. One company can own twenty domains, and one domain can be shared by thousands of users, as with gmail.com, shopify.com stores or github.io pages. A lookup API therefore does two jobs: it decides whether the domain belongs to a single identifiable organisation, and if so it attaches known facts.

Providers build that mapping from public material. The BusinessMCP Company Data API page states that its store is drawn from public company registries, open company datasets, public business listings and company websites, refreshed by its own crawler, and that it does not resell another vendor’s API response. Other vendors lean on licensed databases or user-contributed contact data, and the provenance affects both coverage and what privacy questions you may face.

Fields you can reasonably expect

Field	Typically available	Caveat
Company name	Yes	May be a trading name rather than legal name
Industry	Often	Usually a category label, not a precise classification
Size	Often	A band, not an exact headcount
Location	Often	Headquarters or registered address
Phone	Sometimes	Main line, not direct dials
LinkedIn page	Sometimes	Company page only
Description	Sometimes	Short, from public text
Website status	Sometimes	A dated measurement, not a live check

The provider’s page lists name, industry, size, location, phone and LinkedIn for lookups, and its comparison with other APIs says it carries no funding or intent data. If your use case needs revenue or technology stack, confirm that before you integrate; its guide notes that the tech_stack field is empty.

Key takeaway: domain lookup returns facts about an organisation, not about the person who visited. Keep those two things separate in your data model.

Why some domains come back empty

Expect misses, and expect them for ordinary reasons:

• Very new or very small businesses with no registry footprint or listing.
• Parked or dead domains where no business is operating.
• Platform and subdomain sites where the domain belongs to a host, not a company.
• Brand platforms. The provider states that for domains such as google.com it returns name only, because a listing hosted there does not belong to that company.
• Personal mail domains, which should never be looked up in the first place.

Treat each as information. A miss on a freshly registered domain from a signup is a hint that the signup is a very small outfit or a throwaway.

Normalise before you look up

Cleaning domains is free and saves money on any pay-per-call plan. A reliable routine:

1. Lowercase everything.
2. Remove protocol (https://) and any path or query string.
3. Strip a leading www..
4. Reduce email addresses to the part after @.
5. Drop domains on a blocklist of free mail providers.
6. Deduplicate, and keep the original-to-clean mapping for your own records.

The result is your cache key. The same provider’s guide recommends exactly that approach, with hits kept about 30 days. For batches, see bulk company lookup; for emails specifically, work email to company lookup goes deeper.

Subdomains and multi-brand groups

Decide up front whether you roll subdomains up to the registrable domain. For most B2B work you should: app.acme.com and www.acme.com are one account. Groups with many brands are harder. A holding company’s brands may each have their own domain and record, and your CRM must decide whether to merge them. No lookup API will make that business decision for you.

Testing coverage on your own list

The only coverage number that matters is the one on your own domains. Take a few hundred, resolve them, and compute found rate by segment: enterprise, mid-market, small business, non-profit, region. Then hand-check a sample of found records against each company’s website to estimate accuracy. The free company lookup tool is a quick way to eyeball individual results first.

If found rates look low in one segment, that is the data telling you where the vendor is thin. It may still be a good fit if your highest-value segment is well covered. Our guide to choosing among providers shows how to weigh that.

Keeping the output honest

Store a source label and a fetched-at date next to every enriched value. When a rep questions a record, you can show where it came from and how old it is. When a vendor changes or you switch providers, you can re-run only the stale rows. And when a domain is marked unknown, schedule a retry in weeks, since young companies do eventually appear in public records.

For a first end-to-end build, the walkthrough on getting company data through an API puts these steps in order.

Worked example of a cleaning run

Imagine a spreadsheet of 1,000 rows with messy website values. After lowercasing and stripping protocol, paths and www, you find 940 non-empty values. Removing free-mail domains takes it to 910. Deduplicating leaves 780 unique domains. Checking your cache drops another 120 that were looked up last month. You send 660 to the API. Even before the first call, you have eliminated a third of the spend. This is why cleaning is the highest-return step in any enrichment project.

Interpreting partial results

A result can be found but sparse: a name and country, with nothing else. That usually reflects a source with limited public data for that company, which is common for small businesses. Store what you have and leave the rest null. Resist the urge to infer industry from the name or size from the domain length. A later refresh may fill the gaps, and a wrong guess today will be harder to remove than a blank.

Where this fits in the bigger picture

Domain resolution is the base layer. Once a domain maps to a company you can do email-based signup enrichment, search for similar companies with company search, or check whether the site still runs via website status. The BusinessMCP overview of its data endpoints shows how one provider groups these tasks together, alongside IP, site and people sections that cover different needs.