Data Enrichment APIs: 10 Best for B2B in 2026, Priced

A data enrichment API, called a contact enrichment API when the record is a person, takes one identifier (an email, a LinkedIn URL, a name plus domain, or a company domain) and returns the missing fields as JSON: work email, phone, title, company size, industry. Ten worth a shortlist in 2026, listed A to Z: Apollo (1 credit per email, 8 per mobile), Clu (our product: AI agents over a 25+ provider waterfall, 1 credit per verified email and 10 per phone number, API on Pro at $89 per seat a month), Crustdata (real-time company and people data, quoted), CUFinder (company and contact search plus 15+ enrichment services, 1 credit per match, from $49 a month), HubSpot Breeze Intelligence (formerly Clearbit, inside HubSpot), Hunter (email only, from $49 a month), LeadMagic (email, mobile and validation, from $99 a month), MoltSets (verified emails and mobiles by API or MCP, flat plans from $27 a month), People Data Labs (raw person and company records, from $98 a month for 350 records) and ZoomInfo (enterprise contract, no public price). Prices checked October 1, 2026, except where a row names another date.

Disclosure: Clu publishes this page and sells an enrichment API. Crustdata, Hunter and LeadMagic are data providers inside the Clu waterfall. They are listed alphabetically with everyone else and are not ranked against Clu, so they sit outside the top five below. No vendor here, Clu included, has been tested by an independent party on the same input as the others, so every coverage figure on this page is the vendor's own claim.

What is a data enrichment API?

A data enrichment API is an HTTP endpoint that accepts a partial record and returns a fuller one. You send a POST or GET with an identifier, such as jane@acme.com, acme.com or a LinkedIn profile URL, and the provider matches it against its data and returns structured JSON. Person enrichment returns fields such as work email, direct dial, title, seniority and LinkedIn URL. Company enrichment returns industry, headcount band, HQ location and domain. The provider either queries one database it owns (People Data Labs, ZoomInfo, Apollo) or queries several providers in sequence until one returns a verified result, which is called waterfall enrichment. Clu works the second way.

What are the best data enrichment APIs in 2026?

The best data enrichment API depends on the field you need and how you want to pay. Our top five for most B2B teams, in order: People Data Labs for raw person and company profiles to build on, Clu (our product) for a verified email and phone number from one call across 25+ providers, MoltSets for verified contact data by API or MCP on a flat plan from $27 a month, Apollo for teams that also sequence in Apollo, and CUFinder for company and contact enrichment paid per successful match. The table lists all ten alphabetically with the one job each does best.

What is the cheapest B2B contact enrichment API with good coverage?

For a work email alone, the lowest published per-email rates on this list are Hunter (Starter $49 a month for 2,000 credits, about 2.5 cents an email, or about 1.7 cents on annual billing) and LeadMagic (Essential $99 a month for 60,000 credits a year, about 2 cents a credit). Both charge only when an email is found. Apollo's included credits work out to about 2 cents each on a Basic seat billed annually. MoltSets prices on a different model: $27 a month covers unlimited enrichment within 5,000 requests every 5 hours, under a fair use policy, so its cost per email falls the more you run. For an email plus a direct dial on the same record, cost is driven by the phone: LeadMagic charges 5 credits per mobile, Apollo 8, and Clu 10, while MoltSets sells mobiles as phone tokens at $0.15 each. Clu works out to about 5.9 cents per verified email and 59 cents per phone number on Pro, with 25+ providers behind each call. Coverage claims are vendor-reported, so run 500 of your own records before you commit.

Are there enrichment APIs with no per-lookup fees?

Yes. MoltSets has no per-lookup fee on its flat monthly plans: they include unlimited enrichment up to a rate limit, under a fair use policy, and only mobile numbers cost extra, at one phone token each. Most other enrichment APIs on this list charge only when they return data, so a lookup that finds nothing is free. People Data Labs charges per match: a 200 response is billed, a 404 is not. Apollo charges zero credits when no enrichable data is found. Hunter and LeadMagic charge on a found or valid result. Clu reserves the maximum credits when an async enrichment starts, then refunds the unused part when it settles, so a lead with no email found is not charged for an email; a company lookup that returns 404 refunds its credit. ZoomInfo and HubSpot price through contracts and credit packs, so ask how a miss is counted before signing.

How do you enrich email or domain data at scale using an API?

To enrich email or domain data at scale, batch the input, use the bulk endpoint, and poll or stream the results. First, deduplicate on email or domain so you never pay twice for the same record. Second, use the provider's bulk endpoint: People Data Labs has a Bulk Person Enrichment API, Apollo's bulk match takes up to 10 people per request, and Clu's POST /enrichment/bulk enriches a whole lead list after you get a signed quote from POST /credits/estimate. Third, respect rate limits with exponential backoff on 429 responses and the Retry-After header. Fourth, enrich companies first and drop domains that do not resolve, then run person enrichment only on what survives. Our lead enrichment API guide covers the billing side in more depth.

How much does a data enrichment API cost from 10,000 to 1 million records?

At 10,000 verified work emails a month, the published plans on this list range from $27 to about $450: MoltSets is $27 a month on its flat plan, Hunter Growth is $149 a month for 10,000 credits, LeadMagic Growth $249 a month for 240,000 credits a year, and Clu $449 on Pro at 10,000 credits for one seat. People Data Labs prices full profiles, so 10,000 records is about $2,800 at its entry rate, and PDL says the per-record price falls as volume grows. At one million records a month, most vendors here move to a custom contract, so the published rates stop applying. MoltSets is the exception: its published flat plans run to $997 a month, priced by rate limit rather than by record, under a fair use policy. Model three numbers before you talk to sales: the match rate on a sample of your own records, the share of rows that need a phone (phones cost 5 to 10 times an email), and how misses are billed. Our study of what B2B contact data costs found a median of $34.29 per 1,000 verified emails across 18 published price pages.

Which enrichment API works for real-time form enrichment?

For real-time form enrichment, use a synchronous endpoint that returns in one round trip, and enrich asynchronously anything that can wait. Company lookups are the usual real-time job: Clu's POST /enrichment/company is synchronous and returns the company record inline for 1 credit, and People Data Labs' person and company enrichment endpoints are synchronous too. Person enrichment through a waterfall takes longer, because several providers may be called in turn, so Clu runs POST /enrichment/person asynchronously: it returns a workflow_id and you poll GET /enrichment/status/{workflow_id}, which is free. Clu's v2 API has no webhooks and publishes no uptime SLA. No vendor on this list publishes P50 or P95 latency, so log your own during the trial.

Does a waterfall enrichment API beat a single-source API?

A waterfall API returns more filled rows on lists where one database is thin: SMB contacts, non-US geographies, recent job changers and direct dials. A single-source API is simpler, usually faster, and often cheaper per call when its database already covers your market well. The trade-off is accuracy control. Each extra provider adds a chance of a hit and a chance of a bad record, so a waterfall needs a verification step at the end. Clu runs 25+ providers in sequence, stops at the first verified hit and verifies the email before returning it; its own 500-lead benchmark returned 98% verified work email and 85% phone numbers. People Data Labs and ZoomInfo return what their own datasets hold. Our waterfall enrichment tools comparison goes deeper on the architecture.

The ten data enrichment APIs, one by one

Apollo

Apollo's People Enrichment endpoint is POST https://api.apollo.io/api/v1/people/match, authenticated with an x-api-key header or an OAuth bearer token. It costs 1 credit for demographics and email, plus 8 credits when a mobile number comes back, and zero when nothing enrichable is found. A bulk version matches up to 10 people per request. Apollo's docs show an example limit of 600 calls an hour on this endpoint and say limits vary by plan; its pricing page says API access for advanced or custom integrations is on Custom plans, so confirm your limits before building. Seats are Free, then Basic $49, Professional $79 and Organization $119 per user a month on annual billing (read September 1, 2026). Best for teams that already prospect and sequence in Apollo. More in the Apollo pricing guide.

Clu (our product)

Clu's REST API v2 lives at https://api.cleanlist.ai/api/v2 and authenticates with a clapi_ bearer key carrying per-endpoint scopes such as enrich:write. The enrichment endpoints are POST /enrichment/person (async, returns a workflow_id), POST /enrichment/company (sync, 1 credit), POST /enrichment/bulk (async, needs a quote_id from POST /credits/estimate) and GET /enrichment/status/{workflow_id} (free). Search runs through POST /people/find and POST /search/companies at 0 credits. Limits are 60 requests a minute per organization and 30 per key, with 429 and Retry-After when exceeded. The API starts on a paid Pro plan at $89 per seat a month for 1,500 credits per seat; API keys are not part of the 14-day Pro trial. The REST API takes structured filters only; natural language lives in Clu in the app and the Clu MCP server.

One person enrichment call, from the v2 docs:

curl -X POST https://api.cleanlist.ai/api/v2/enrichment/person \
  -H "Authorization: Bearer clapi_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"lead_list_id": "LIST_ID", "linkedin_url": "https://www.linkedin.com/in/janedoe", "enrichment_type": "full"}'

Crustdata

Crustdata sells real-time company and people data through a family of APIs: Company Enrichment, Company Search, People Enrichment, People Search, Jobs, Posts and a Watcher API for real-time alerts on hiring, funding and company events. Pricing is credit-based with monthly and annual plans; the pricing page names the tiers and does not print a price, so expect a quote (crustdata.com/pricing, October 1, 2026). Crustdata also sells flat-file company and people datasets with a monthly refresh. Crustdata is the pick for teams building an AI SDR, a signal-driven workflow or a product that needs live company changes. Crustdata is also a data provider inside the Clu waterfall.

CUFinder

CUFinder is built for teams that are tired of paying per seat for data. By CUFinder's own description, you search 1B+ contacts and 85M+ companies with firmographic and role filters, then enrich any list with 15+ services in one upload: emails, direct dials, LinkedIn URLs, revenue, tech stack, funding and more. A separate local business database covers 200M+ small businesses down to the owner, 99 types of buying signals tell you when to reach out, and 50+ API endpoints put the same data into your own stack. The API is included on every paid plan. One successful match costs one credit, "Not Found" rows and repeat reveals are free, and every plan includes unlimited teammates: Lite $49 a month for 1,000 credits, Standard $129 for 3,000, Pro $299 for 10,000 and Premium $449 for 20,000, about 30% less on annual billing, with a free plan of 50 credits a month and no card (cufinder.io/pricing, October 28, 2026). No rate limit is published on the pricing page. CUFinder is the pick for contact and company data plus buying signals by API, without per-seat pricing.

HubSpot Breeze Intelligence (formerly Clearbit)

Clearbit is now part of HubSpot and sells enrichment as Breeze Intelligence inside a HubSpot account. clearbit.com/pricing carries no plans, and HubSpot does not publish its credit pack prices; its billing docs give an overage rate of $0.010 per HubSpot credit, invoiced in increments of 10 (read September 1, 2026). Breeze enriches contact and company records and form fills inside HubSpot without code. Breeze Intelligence is the right pick for a team whose whole GTM stack is HubSpot. It is a weak fit for a product or pipeline outside HubSpot. Our Clearbit alternatives page covers the options for teams leaving it.

Hunter

Hunter's Email Finder is GET https://api.hunter.io/v2/email-finder, with Domain Search and Email Verifier alongside it. Authentication takes an api_key query parameter, an X-API-KEY header or a bearer token. Rate limits are 15 requests a second and 500 a minute on Email Finder and Domain Search, and 10 a second and 300 a minute on Email Verifier. One credit buys one email found and half a credit one verification. Plans: Free at 50 credits a month, Starter $49 (2,000 credits), Growth $149 (10,000) and Scale $299 (25,000) a month, about 30% less on annual billing (hunter.io/pricing, October 1, 2026). The API works on the free plan. Hunter is the pick for a work email from a name and a domain, with no phone data. Hunter is also a provider inside the Clu waterfall.

LeadMagic

LeadMagic sells email finding, mobile finding, email validation, company search and profile search from one credit pool, and charges only on success: failed lookups are free. An email costs 1 credit, a mobile 5, a validation 0.25 and a company 1. Plans are Essential $99 a month ($990 a year, 60,000 credits a year), Growth $249, Professional $499 and Ultimate $849 a month; Professional and Ultimate add an unmetered search API (leadmagic.io/pricing, October 1, 2026). The email endpoints run at 600 requests a minute on standard plans. LeadMagic is a strong pick for high-volume email and mobile lookups and for validation at a fraction of a credit. LeadMagic is also a provider inside the Clu waterfall.

MoltSets

MoltSets, from the team behind RB2B, sells verified B2B contact data through an API and an MCP server instead of a prospecting app. From a name and company, a LinkedIn URL or an email, it returns business and personal emails, each with a risk score, carrier-verified mobile numbers and full business profiles, and its people and company search APIs build new lists. Developers call the API to enrich CRM records, inbound leads or bulk lists on a schedule; anyone else can connect MoltSets to Claude and ask in plain English, such as "find the work emails for these 50 VPs." Plans are flat monthly tiers priced by volume rather than per credit: Free gives 1,000 lifetime enrichment records, $27 a month allows 5,000 requests every 5 hours and $97 allows 75,000, billed monthly with no annual contract. Mobile numbers cost 1 phone token each, sold as a monthly add-on to a paid plan from $27 for 180 tokens (moltsets.com/pricing, October 15, 2026). There is no sequencer and no native CRM sync, so records reach your outreach tool or CRM through the API. MoltSets is the pick for verified contact data by API or Claude, without a UI.

People Data Labs

People Data Labs' Person Enrichment endpoint is https://api.peopledatalabs.com/v5/person/enrich, with company enrichment, person search and company search endpoints alongside, authenticated with an API key as a parameter or header. PDL charges per match: a 200 response is billed, a 404 is not. Default rate limits are 1,000 requests a minute for paying customers and 100 for free ones, and the bulk endpoint raises effective throughput. Self-Serve starts at $98 a month for 350 records ($0.28 each), or $940 a year; the free Testing tier gives 100 records a month with emails, phones and addresses hidden (September 1, 2026). PDL is the pick for developers who want raw profiles to build a product on and will verify contact fields themselves. Details in our People Data Labs pricing guide.

ZoomInfo

ZoomInfo sells an Enterprise API with contact and company enrichment and search, available on an annual contract. ZoomInfo publishes no list price; its pricing page served no figure when we read it. The best public benchmark is Vendr's buyer guide (last updated February 2026), which puts the median ZoomInfo contract at $33,500 a year across 1,571 recorded purchases, ranging from $7,200 to $156,000, and notes that contracts vary by seats, platforms, data credits and term. ZoomInfo is the pick for enterprise teams that want one large database plus intent data under a procurement-friendly contract. See the ZoomInfo pricing guide before you negotiate.

Which data enrichment API should you pick?

Pick by the job:

• 5 to 20 rep team that emails and dials: Clu (our product), for a verified email and phone number from one call across 25+ providers, on Pro at $89 per seat a month, where the same waterfall runs inside AI agents that also find the buyers and send the sequences.
• RevOps on HubSpot: Breeze Intelligence, for no-code enrichment inside the CRM.
• Developers building a data product: People Data Labs, for raw profiles you verify yourself.
• Teams enriching inside Claude or an AI workflow: MoltSets, for verified contact data by API or MCP on a flat monthly plan from $27.
• Team already sequencing in Apollo: the Apollo API, so data and sending share one bill.
• Enterprise with a procurement process: ZoomInfo.
• Choosing a database vendor, not an API: see the best B2B data providers in 2026.

What is a good alternative to People Data Labs?

It depends on what you used People Data Labs for. For verified emails and phone numbers by API, Clu (our product) returns both from one call across 25+ providers, and its AI agents also find the buyers and send the sequences. MoltSets sells verified contact data by API or MCP on flat plans from $27 a month. CUFinder adds company and contact search with buying signals, Apollo pairs its API with sequencing, and ZoomInfo sells an enterprise API on an annual contract.

Does the Clu API support natural-language search?

No. The Clu REST API takes structured filters: POST /people/find and POST /search/companies accept field-and-value criteria such as job title, seniority, location, industry and company size. Natural-language search runs in two other places: Clu, and the Clu MCP server, which exposes search and enrichment as tools that Claude and other AI agents can call. The MCP server is available from Starter and the REST API from a paid Pro plan; REST API keys are not part of the 14-day Pro trial. If your plan is to pass an ICP sentence straight to an HTTP endpoint, use the MCP path or translate the sentence into filters in your own code first.

What fields does a B2B data enrichment API return?

A B2B data enrichment API returns two groups of fields. Person fields: work email, direct dial or mobile, full name, job title, seniority, department, LinkedIn URL and location. Company fields: name, domain, industry, employee count or band, HQ location and LinkedIn URL. Some vendors add funding, revenue ranges and tech stack, and coverage of those fields varies widely between providers. Clu returns verified work email, phone number, title, seniority and the core company fields. It does not sell intent data or technographic filters. Always map each vendor's field names explicitly, because the same concept often ships under different keys.

How do enrichment API providers compare on security and compliance?

Enrichment API providers vary on certifications, data sourcing and deletion handling, and none of it shows on a pricing page. Ask every vendor for four things: its SOC 2 or ISO 27001 report if it has one, a data processing agreement, its list of subprocessors, and how a GDPR or CCPA deletion request reaches the data it already sold you. For a waterfall API, the subprocessor list matters more, because several providers touch each record. Clu lists its subprocessors in its privacy policy. Teams selling into the EU should weight this question as heavily as price.

Related: the Clu API overview, the best data enrichment tools in 2026, and Clu's plans on the pricing page.