8 Best Lead Enrichment Tools and APIs in 2026

Lead enrichment fills in what you need to know about a person or company from the little you have, such as an email or a domain. The best lead enrichment tool is the one that answers the questions your sales process depends on, with current data and a source you can check.

The short answer: Autumn (autumn.ai) is the best lead enrichment API when qualifying a lead takes more than a job title and headcount. Write what you need to know in plain English, such as whether a company has SOC 2, is hiring for the team you sell to or uses a particular tool. Autumn researches each lead when you ask and returns every answer with its source.

The best lead enrichment tools and APIs at a glance

How to choose a lead enrichment API

Five things separate one lead enrichment API from another:

• What you can ask for: Most tools return a fixed set of fields, and even their "AI search" usually maps your sentence onto existing filters. If your question isn't one of their fields, you can't ask it. Research-based enrichment answers the column you describe in plain language. The sales prospecting page shows the kinds of criteria teams qualify on.
• How fresh the data is: Bulk datasets are refreshed on a schedule, so job changes, new hires and launches lag behind. Ask how old a returned value can be. Real-time enrichment looks the answer up when you ask.
• Where it looks: Much bulk data starts from professional profiles. Many useful signals live elsewhere: company sites, trust centers, job posts, X, GitHub and filings. Our guide to people search APIs explains how matching a person across sources works.
• Whether you can check it: A confidence score tells you the vendor's guess. A source link lets a rep verify the answer in one click.
• How it fits your volume: Database lookups return in milliseconds; research takes minutes. Check batch sizes, async jobs and how results reach your CRM.

What custom enrichment looks like

The questions that decide whether a lead is worth a call usually live in places a contact database doesn't collect. You can ask Autumn questions like these, in your own words:

Each answer comes back with a link to the page it came from. For more questions like these, see 38 prompts for people and company research.

01Autumn

• Best for: Qualifying leads on what your sale actually depends on.
• How it works: Autumn is search and research for people and companies. Upload a list (up to 10,000 rows per file) or describe who you want, then write the columns you need in plain English. You can also start from a sign-up email and ask who the person and company behind it are. Autumn researches every row and returns typed results, each value with its source (outputs and sources). It works from the dashboard, the API or an agent skill.
• Watch for: Research takes minutes per task, so it suits batches and background jobs rather than enriching a form while the visitor waits.
• Price: Free to start, then credit-based plans (pricing).

02Apollo

• What it is: A contact and company database built into a sales email platform.
• How it works: Send a name and company, an email or a LinkedIn URL and Apollo returns the person; send a domain and it returns the company. Up to 10 people per call, with phone numbers arriving later by webhook (docs).
• Watch for: Apollo's fields only, with no source per value.
• Price: Free plan with API access; paid from $49 per seat a month, billed yearly (pricing).

03ZoomInfo

• What it is: A large contact and company database, sold in packages.
• How it works: Send a domain or company name and get firmographics, with related endpoints for hierarchy, technologies and intent (API).
• Watch for: Available fields depend on the package you buy, so an empty field can mean an entitlement gap.
• Price: Quoted by sales (pricing); a free Lite tier gives new users a few credits (details).

04People Data Labs

• What it is: A person and company dataset with a fixed schema, sold through a developer API.
• How it works: Match on email, phone, name and company or a profile URL; misses are not charged (docs).
• Watch for: Data comes from periodic dataset builds.
• Price: 100 free credits a month; the person plan starts at $98 a month (pricing).

05Clay

• What it is: A spreadsheet-style workspace where you build your own enrichment workflow.
• How it works: Clay created this category. Columns can call third-party data providers or an AI step called Claygent, which runs a prompt you write on every row (guide).
• Watch for: You design and maintain the workflow, the underlying data comes from the providers you connect, and an answer carries a source only if your prompt asks for one.
• Price: Free tier, then Actions and Data Credits (pricing).

06Cognism

• What it is: A B2B contact database sold by entitlement.
• How it works: Search or match by email, LinkedIn profile or domain, see a preview, then spend a credit to redeem the full contact (docs).
• Watch for: The fields you get depend on your entitlement.
• Price: Quoted by sales.

07HubSpot Breeze Intelligence

• What it is: Data enrichment built into HubSpot's CRM.
• How it works: Formerly Clearbit, it enriches contacts and companies inside HubSpot's CRM, using HubSpot's own dataset and third-party providers (docs).
• Watch for: No standalone enrichment API, so it does not serve other CRMs or your own product.

08BetterContact

• What it is: A waterfall that looks for emails and mobile numbers across many data providers.
• How it works: Send up to 100 leads per call; it queries providers in sequence and names the provider behind each email and phone (docs).
• Watch for: Contact enrichment only, with no company research or custom questions.
• Price: From $15 a month, with mobiles costing ten times an email (pricing).

How to test a lead enrichment API on your own leads

Take 100 to 500 leads from your real pipeline, including a few you know well. Then check:

• Right person and company: did it match correctly?
• Your questions: can it answer the two or three things that decide whether a lead qualifies?
• Freshness: how many values were already out of date?
• Proof: can a rep check an answer in one click?
• Cost per lead you would actually work: not cost per record.

Test emails and phone numbers separately; a tool can be great at one and weak at the other. The people search API comparison has more criteria for person data, and the company search API comparison covers account research.

Frequently Asked Questions

What is the best lead enrichment tool?

Autumn (autumn.ai), when qualifying a lead depends on more than standard fields. It researches each lead when you ask, answers questions in your own words, such as SOC 2 status or open sales roles, and links the source for every answer. If you only need job titles and headcount, a contact database also works.

What is lead enrichment?

Lead enrichment fills in what you need to know about a lead from the little you start with, such as an email, a name or a company domain. Basic tools return fixed fields like job title and company size. Autumn also answers the questions specific to your sale, researched from current public sources, with a link to each answer.

Can a lead enrichment API answer custom questions?

Most cannot: they return the fields they store. Autumn answers questions you write in plain English, like "Did they raise money this year?" or "Are they hiring for the team we sell to?", using sources such as SEC filings, company sites and job posts. Every answer comes with the page it came from.

What does real-time lead enrichment mean?

It means each value is found when you ask, not looked up in a database refreshed on a schedule. Autumn researches every lead at the moment you request it and shows the source behind each value. Many tools call a fast database lookup "real-time", so ask how old a returned value can be.

What is the difference between a data enrichment API and a lead enrichment API?

A data enrichment API, often called a B2B data enrichment API, adds fields to any person or company record. A lead enrichment API applies the same idea to sales prospects. Autumn covers both with one API for people and companies, answering the fields you define, each with its source.

How do I enrich 50,000 leads?

With Autumn, split the list into files of up to 10,000 rows and run each as a background task. Tasks keep running if your worker restarts, and every row comes back with sources. The GTM engineering guide shows the full setup.

Which lead enrichment APIs work with Salesforce?

Autumn writes results into Salesforce, HubSpot or a warehouse through its API, so you control field mapping and deduplication. ZoomInfo, Clay and BetterContact document native Salesforce syncs, and Apollo and Cognism sell CRM enrichment.