Your AI agent is only as reliable as the data powering it. We compared 10 B2B data APIs on accuracy, developer experience, compliance, and AI-native features so you can connect the right one to your workflows.
TL;DR The best B2B data APIs for AI agents in 2026 are Lusha (best overall for verified contacts with native MCP and REST API), Apollo.io (best value for high-volume agentic workflows), and People Data Labs (best for developer-first enrichment at scale). We compared 10 APIs below.
What is a B2B data API?
A B2B data API is a programmatic interface that lets software applications query verified business contact and company data in real time, delivering structured JSON responses that AI agents, automation workflows, and CRM systems can act on immediately. Instead of managing static spreadsheets or manually importing CSVs, an AI agent calls the API, gets back a verified email address, direct dial, or firmographic profile within milliseconds, and uses that data to route, score, or personalize its next action.
- What it delivers: Person-level data such as verified emails, direct dials, job titles, and LinkedIn URLs, plus company-level data including firmographics, technographics, revenue bands, employee count, and buying signals.
- Who builds with it: RevOps engineers, GTM architects, AI developers, and automation teams connecting prospecting workflows to CRMs, sales engagement tools, and LLM-powered agents built on Claude, GPT, n8n, or Make.
- Why accuracy matters: B2B contact data decays at roughly 30% per year, meaning an AI agent built on stale records generates enrichment errors that cascade through downstream scoring and routing logic. A single bad phone number poisons a dialer sequence; a wrong title breaks personalization.
- What separates good from bad: Verified accuracy (not just claimed rates), compliance coverage for GDPR and CCPA, rate limits and response latency at scale, and structured output that works cleanly with agent orchestration frameworks.
Below, we evaluated 10 APIs against the criteria that matter most for AI agent builders: data quality, compliance, developer experience, and pricing.
How we evaluated
We assessed each API on six criteria: verified data accuracy (email and phone), database size and geographic coverage, developer experience (documentation, response structure, SDKs), compliance posture (GDPR, CCPA, and relevant certifications), AI-native features (MCP support, webhooks, real-time enrichment), and pricing transparency including free tier availability.
- Data accuracy: Claimed vs. real-world match rates, verification methodology, and data freshness cadence
- Coverage: Database size, geographic strength, and depth of company vs. person records
- Developer experience: API documentation quality, SDKs, response schema consistency, and latency
- Compliance: GDPR and CCPA alignment, data sourcing transparency, opt-out mechanisms, and certifications
- AI-native features: MCP server support, webhook delivery, real-time vs. batch enrichment, and integration with agent frameworks
- Pricing: Starting price, free tier value, credit-based vs. usage-based model, and predictability at scale
Quick comparison
| # | Tool | Best for | Starting price | Free plan |
1. Lusha
Lusha is a B2B sales intelligence platform built around a verified contact and company database of 300M+ contacts, 152M+ emails, and 30M+ company profiles. For AI agent builders, the standout is infrastructure readiness: Lusha ships a REST API for contact and company enrichment alongside a native MCP connector that lets AI agents running on Claude or any MCP-compatible framework pull verified prospect data directly, without needing a separate integration layer. You can also read about how teams are putting it to work in Lusha in Claude real-world deployments.
Data accuracy is where Lusha earns its #1 position: 98% email accuracy and 86% phone accuracy, verified continuously through a crowdsourced contributor community plus AI enrichment. That combination means your enrichment calls return results you can act on, not results you need to manually verify before passing downstream. The API supports contact enrichment, company enrichment, webhook delivery, and bulk CSV processing, giving AI agents both synchronous lookups and batch-scale operations.
Compliance coverage is broad: GDPR, CCPA, SOC 2 Type 2, ISO 27001, ISO 27017, ISO 27701, ISO 31700, and a public Trust Center with opt-out. For teams building AI workflows that touch EU contacts, that posture matters, and Lusha treats it as a core product feature rather than a legal checkbox.
Pros
- Native MCP server: AI agents query verified B2B data without a custom integration
- 98% email accuracy and 86% phone accuracy, independently cited by customers
- Real-time buying signals (job changes, funding, technographics) available via the same API
- Broad compliance: GDPR, CCPA, SOC 2 Type 2, ISO 27001 + Trust Center
- Free tier gives developers 40 credits per month to prototype without commitment
Cons
- Database size (300M+ contacts) is smaller than ZoomInfo’s claimed 260M+ but the accuracy vs. volume trade-off favors accuracy for most AI use cases
- EMEA phone coverage is strong but trails Cognism’s Diamond Data verification for certain European markets
Pricing
Free plan: 40 credits per month, no credit card required. Starter: $49.90/mo ($37.45/mo billed annually). Professional: $69.90/mo ($52.45/mo annually) with rollover credits. Premium: $399.90/mo ($299.95/mo annually) with 3,400 credits and 5 seats. API access is included across paid plans.
What users say
“It provides accurate B2B contact and company data, allowing sales and marketing teams to reach decision-makers faster.”
“The content and data that Lusha provides are pretty vast, which is great for mass prospecting.”
Best for
GTM teams, RevOps engineers, and AI developers who need a verified B2B data layer with native agentic connectivity, and who want buying signals alongside contact data in a single API call.
2. Apollo.io
Apollo.io is one of the most widely adopted B2B data platforms in the mid-market, combining a 275M+ contact database with a built-in outreach sequencer and a REST API that integrates cleanly with automation tools like Clay, n8n, and Zapier. For AI agent builders who need volume at a low entry price, Apollo is the practical default: it offers generous credit allocation on its free tier and a well-documented API that returns contact data including emails, phone numbers, job titles, LinkedIn URLs, and basic company firmographics.
Phone data quality is the known gap. Real-world hit rates on direct dials hover around 55%, which is workable for email-first AI workflows but limiting for dialer automation. If your agent’s primary action is cold email enrichment, Apollo’s 80%+ email accuracy is competitive. If it needs direct dials at scale, consider pairing Apollo with a dedicated phone enrichment source.
Pros
- 275M+ contacts with a well-documented public REST API
- Free tier includes 50 email credits per month and API access
- Native Clay integration for waterfall workflows
- Affordable entry pricing at $49/user/mo with community-verified data
Cons
- Phone accuracy inconsistent at roughly 55% real-world hit rate
- Customer support response times frequently criticized in G2 reviews
- Credit-based model restricts heavy API users without plan upgrades
Pricing
Free: 50 email credits per month. Basic: $49/user/mo (annual). Professional: $79/user/mo. Custom enterprise plans available.
Best for
Teams running high-volume, email-first agentic outbound who need a large verified database at the lowest entry price point in the category.
See how it compares: best Apollo alternatives.
3. People Data Labs
People Data Labs (PDL) is purpose-built for developers. The platform exposes a 3B+ record database (people and companies) through a clean REST API with thorough documentation, code samples in Python, Node.js, Ruby, Go, and cURL, and predictable JSON response schemas that integrate cleanly with LLM pipelines. Each person record returns 44+ data points: current and past employment, education history, verified emails, social profiles, and inferred skills. Company records include firmographics, tech stack, revenue bands, and funding history.
PDL is not a GTM tool with a workspace, it is infrastructure. There is no Chrome extension, no CRM integration, and no prospecting UI. You get an API key, documentation, and data, which is exactly what AI agent builders often want: no forced product opinions, just clean enrichment endpoints. SOC 2 Type 2 certified. The free plan covers 100 lookups per month, enough to prototype before committing.
Pros
- 3B+ person and company records with developer-first API design
- 44+ data points per person record including work history and skills
- SOC 2 Type 2 certified with transparent data sourcing
- Free tier at 100 lookups per month for prototyping
- No workspace, no UI overhead: pure API infrastructure
Cons
- Match rates are not 100%, and enterprise pricing climbs quickly at scale
- Primarily US-focused; international coverage less strong than PDL’s claimed total
- No built-in buying signals or intent data
Pricing
Free: 100 person and company lookups per month. Pro: $98/mo (350 credits). Enterprise: custom pricing from approximately $2,500/mo. Per-credit pricing at $0.28/match on Pro, scaling down at volume.
Best for
Developers and data engineers building AI enrichment pipelines who want the largest available B2B record set behind a developer-native API without a workspace layer or GTM product forcing a specific workflow.
4. Clearbit (HubSpot Breeze)
Clearbit was acquired by HubSpot in 2023 and is now integrated into the HubSpot Breeze AI suite. For teams whose AI workflows are rooted in HubSpot, the Clearbit enrichment API remains best-in-class: real-time company and contact enrichment fires the moment a new record enters HubSpot, form shortening reduces friction at the top of funnel, and buyer intent data surfaces which companies are actively researching your category. The API delivers sub-200ms responses on enrichment calls for US and North American records, with 200M+ contacts in its database.
The hard constraint is HubSpot dependency. Without an active HubSpot subscription, Clearbit provides almost no standalone value. Teams on Salesforce, Pipedrive, or a custom CRM should look elsewhere. EMEA data quality also drops meaningfully outside the US, a known limitation reflected across G2 reviews.
Pros
- Real-time enrichment API with sub-200ms response times for US records
- Native HubSpot integration requiring zero custom code for HubSpot users
- Form shortening improves conversion rates on inbound workflows
- Buyer intent data identifies companies researching your category
Cons
- Requires a HubSpot subscription; standalone value is minimal
- EMEA and APAC data quality significantly weaker than US coverage
- Combined HubSpot + Clearbit cost is high for smaller teams
Pricing
Clearbit is bundled as a usage-based add-on to HubSpot, starting around $75/mo. No standalone free plan; requires active HubSpot subscription.
Best for
HubSpot-native teams building AI workflows entirely within the HubSpot ecosystem who need real-time enrichment without custom integration work.
5. Clay
Clay is not a data provider in the traditional sense; it is an AI-powered enrichment and automation platform that aggregates 100+ B2B data sources (including Lusha, ZoomInfo, Apollo, Hunter, and Cognism) into a single waterfall workflow. When one provider misses a record, Clay automatically falls through to the next, giving your agent access to the highest match rates available without managing multiple API contracts. The platform also ships AI research agents that can browse websites, extract information, and draft personalized outreach, all wired into the same enrichment flow.
The trade-off is operational complexity and total cost. Clay’s credit cost plus underlying provider costs can add up quickly at scale, and the platform genuinely requires a technical RevOps operator to configure well. If your team already has a dedicated Clay operator and uses Lusha as one of its data sources, the Lusha + Clay integration gives you verified accuracy through the Clay waterfall without giving up data quality. See how teams have automated inbound and outbound using Lusha MCP with n8n for a comparable no-code workflow path.
Pros
- Aggregates 100+ data providers for the highest available match rates
- Built-in AI research agents for prospect research and email personalization
- Highly flexible: supports custom workflows, webhooks, and CRM sync
- 4.9/5 G2 rating with 250+ reviews
Cons
- Steep learning curve; requires a dedicated RevOps engineer to operate well
- Credit costs plus underlying provider fees add up quickly at scale
- Clay is an orchestration layer, not a data source; you still pay for the underlying providers
Pricing
Free: 100 credits per month. Starter: $149/mo. Explorer: $349/mo. Pro: $800/mo. Enterprise pricing available. Underlying provider costs are separate.
Best for
RevOps engineers and technical GTM builders who need the highest possible match rates across multiple data sources and who have the operational capacity to configure and maintain a multi-provider waterfall.
6. ZoomInfo
ZoomInfo’s API remains the benchmark for enterprise-scale intent data in the US market. The platform combines 260M+ contacts with Bombora-powered intent signals, job change data, web visitor tracking, and technographics, all available via API for teams building AI models that need to score, rank, and route accounts based on active buying behavior. The API surface is wide, documentation is thorough, and native integrations with Salesforce, HubSpot, Outreach, and Salesloft are production-hardened at enterprise scale.
The entry barrier is prohibitive for most teams: annual contracts starting around $15,000/yr, aggressive upselling, and an onboarding process that requires weeks of admin. EMEA and APAC data quality drop significantly compared to US coverage, and real-world email accuracy is closer to 75% than the claimed 85%. If your AI agents operate primarily in the US enterprise market and your organization can absorb the cost, ZoomInfo’s intent layer is genuinely differentiated. Otherwise, the cost-to-value ratio rarely wins at mid-market.
Pros
- Largest US B2B contact database with deepest intent signal coverage via Bombora
- Enterprise-grade API with broad Salesforce and HubSpot integration depth
- AI Copilot features for prospect recommendations and sequence personalization
Cons
- Annual-only contracts from approximately $15,000/yr with aggressive renewal tactics
- EMEA and APAC data quality noticeably weaker than US coverage
- Complex to implement; steep admin overhead for non-enterprise teams
Pricing
No self-serve pricing. Annual contracts typically start around $15,000/yr; enterprise contracts run significantly higher. Trial access only, no free plan.
Best for
Large US-focused enterprise teams running AI-driven ABM or outbound programs who need the deepest available intent data and have dedicated RevOps capacity to manage the platform.
See how it compares: best ZoomInfo alternatives.
7. Cognism
Cognism’s strongest differentiator is Diamond Data, a proprietary human-verified phone number dataset targeting European and UK mobile contacts. Where most providers’ phone accuracy hovers at 55 to 70% for EMEA records, Cognism’s Diamond Data delivers approximately 98% accuracy on the human-verified subset, making it the benchmark for AI agents and dialer automations targeting European buyers. The API supports contact enrichment, company enrichment, and CRM bulk enrichment, with compliance posture (GDPR, CCPA, SOC 2) built into the data sourcing methodology rather than layered on top.
Coverage outside EMEA and the US is limited, the platform requires an annual contract with no transparent pricing, and the Bombora intent add-on costs extra. For teams with a global agent footprint, Cognism pairs well with a provider stronger in APAC and North American coverage.
Pros
- Diamond Data phone verification delivers approximately 98% accuracy on verified UK and European mobiles
- Strongest GDPR compliance posture of any major data provider
- Clean UI and reliable API with good documentation
- 4.6/5 G2 rating with 1,300+ reviews
Cons
- Annual contracts only, no transparent pricing, roughly $15,000/yr to start
- APAC coverage weak; North America trails ZoomInfo and Apollo
- Bombora intent data is a paid add-on, not included in base pricing
Pricing
Custom annual pricing starting approximately $15,000/yr. No self-serve plan. Trial access available.
Best for
EMEA-focused revenue teams building AI dialer or multi-channel outreach agents where phone data accuracy on European mobiles is the primary data quality requirement.
8. Hunter.io
Hunter.io is the simplest and most affordable email discovery API in this list. It indexes 76M+ websites and returns professional email addresses with a confidence score attached to each result, giving AI agents a lightweight signal for deciding whether to proceed with an enrichment or flag it for review. The domain search endpoint is particularly useful for AI workflows targeting a specific company: pass a domain, get back all indexed emails at that organization. The API is well-documented, returns clean JSON, and the free tier’s 25 searches per month covers most low-volume prototyping scenarios.
Hunter does one thing: email. There is no phone data, no company firmographics, no buying signals, and no intent data. For an AI agent that needs more than a verified email address to route and personalize outreach, Hunter is a starting point or a fallback, not a complete data layer.
Pros
- ~91% claimed email accuracy with confidence scoring per result
- Domain search endpoint returns all emails at a company from a single call
- Extremely simple API: minimal setup, clean JSON, zero learning curve
- Affordable at $34/mo annual with a genuine free tier
Cons
- Email only: no phone numbers, company data, or buying signals
- Limited utility for AI agents that need enrichment beyond email verification
- Accuracy still imperfect; bounces occur even on high-confidence results
Pricing
Free: 25 searches per month. Starter: $34/mo (annual, 500 searches). Growth: $104/mo (annual, 5,000 searches). Business: $349/mo (annual, unlimited).
Best for
Small teams and developers building lightweight AI email workflows who need a simple, affordable email discovery API with zero configuration overhead and a real free tier.
9. Diffbot
Diffbot takes a different approach to B2B data: instead of maintaining a proprietary contact database, it runs an AI-powered web crawler across 1.2B+ public websites and extracts structured data from unstructured HTML in real time. The result is a Knowledge Graph of 10B+ entities spanning companies, people, articles, products, and events, all queryable via REST API and returning clean JSON. For AI agents that need to research a company’s recent news, identify new hires, track technology changes, or answer questions about a target account from public sources, Diffbot’s Extract and Knowledge Graph APIs provide data that traditional contact databases do not surface.
Diffbot is not a contact enrichment tool. You will not get verified direct dials or sourced email addresses from it. It sits at a different layer of the AI agent data stack: research and web intelligence rather than prospecting and enrichment. At $299/mo minimum and with a learning curve that requires developer time to configure, it is positioned for teams with a specific unstructured web data use case rather than general-purpose GTM enrichment.
Pros
- AI-powered extraction from any public web page without per-site scraper maintenance
- 10B+ entity Knowledge Graph covering companies, people, articles, and events
- Refreshes every 4 to 5 days, keeping the knowledge graph current
- 4.9/5 G2 rating with strong developer satisfaction scores
Cons
- No contact-level enrichment: no verified emails or direct dials
- $299/mo minimum pricing limits accessibility for smaller teams
- Steep learning curve for non-developers
- Best suited as a complementary research layer, not a standalone B2B data API
Pricing
14-day free trial. Startup: $299/mo. Plus: $899/mo. Enterprise: custom pricing.
Best for
AI developers and data engineers who need an intelligent web data extraction layer for research-oriented agents: competitive intelligence, account research, news monitoring, and knowledge graph queries on top of a base contact enrichment source.
10. RocketReach
RocketReach claims a 700M+ professional profile database, one of the largest in the category by raw count, with API access available on its Essentials plan at $33/mo annual. For recruiters and marketers running AI workflows that need broad reach across roles and industries, the database size is the appeal. The API supports bulk lookup and returns emails, phone numbers, and LinkedIn URLs, with basic technographic and intent data available at higher tiers.
Data accuracy is the documented concern. G2 reviewers tag “Inaccurate Data” and “Outdated Contacts” as the top complaints, and Trustpilot ratings reflect billing and renewal issues. For AI agents where enrichment accuracy directly affects downstream scoring or personalization quality, the mismatch between claimed coverage and real-world accuracy creates operational debt. RocketReach works for use cases that tolerate higher verification overhead or that pair it with a secondary accuracy check.
Pros
- 700M+ claimed professional profiles with a low entry price at $33/mo
- API access on base plan with bulk lookup support
- Broad use case coverage: recruiting, sales, and marketing
Cons
- Data accuracy widely criticized in G2 reviews (“Inaccurate Data” is the top tag)
- Trustpilot rating of 1.2/5 driven by billing complaints and unauthorized renewals
- Main platform UI frequently described as confusing and hard to navigate
Pricing
Free: 5 lookups per month. Essentials: $33/mo (annual). Pro: $83/mo (annual). Ultimate: $207/mo (annual).
Best for
Recruiters and marketers running high-volume AI lookup workflows where broad coverage matters more than per-record accuracy, and where a secondary verification step is already built into the pipeline.
How to choose the right B2B data API for AI agents
The right choice depends on three variables: what your agent does with the data, where your contacts live geographically, and how much your team can absorb in cost and complexity.
- If your agent enriches and routes records programmatically: Prioritize API response structure, accuracy guarantees, and compliance posture. Lusha and People Data Labs are purpose-built for this. See how teams use the Lusha API in RevOps workflows for a practical illustration.
- If your agent needs buying signals alongside contact data: ZoomInfo is the most complete US solution; Lusha’s API returns job change and intent signals at a fraction of the cost for most mid-market use cases.
- If your agent is global with heavy EMEA presence: Cognism’s Diamond Data is the phone accuracy benchmark for European mobiles. Lusha covers global markets with strong US and growing EMEA coverage.
- If your agent is built on Claude or an MCP-compatible framework: Lusha’s native MCP connector eliminates the integration layer entirely. Apollo, ZoomInfo, and others require a REST API wrapper or a middleware tool like Clay.
- If you are building for the first time or prototyping: Start with Lusha’s free tier (40 credits/mo) or People Data Labs’ free tier (100 lookups/mo). Both return structured data that maps cleanly into a test pipeline without a credit card.
- If enrichment accuracy is paramount for downstream AI scoring: A waterfall approach via Clay, pulling from Lusha as the primary source and falling through to a secondary, produces the highest match rates at the cost of operational complexity.
Frequently asked questions
What is the best B2B data API for AI agents?
Lusha is the strongest overall option for AI agents: 98% email accuracy, 86% phone accuracy, a native MCP server for agent-native integration, and real-time buying signals alongside contact data. Apollo.io is the best value choice for high-volume email-first workflows. People Data Labs is the best fit for developers building enrichment pipelines who want pure API infrastructure without a GTM product layer.
Do B2B data APIs support AI agent frameworks like Claude or n8n?
Yes, with varying levels of native support. Lusha ships a native MCP connector compatible with Claude and any MCP-compliant agent framework. Apollo.io and ZoomInfo offer REST APIs that require a custom integration or a middleware tool like Clay or n8n. Clearbit is HubSpot-native and requires HubSpot’s AI features to connect with external agents. People Data Labs offers a clean REST API that integrates with any agent framework using standard HTTP calls.
How do I know if a B2B data API is GDPR-compliant?
Look for three things: a publicly documented data sourcing methodology, an active opt-out mechanism for data subjects, and explicit compliance certifications such as GDPR, CCPA, ISO 27001, or SOC 2 Type 2. Lusha, Cognism, ZoomInfo, and Apollo all provide compliance documentation. For EU-focused use cases, Cognism has the strongest compliance posture on phone data; Lusha covers the broadest compliance surface across all data types with GDPR, CCPA, SOC 2 Type 2, ISO 27001, ISO 27017, ISO 27701, and ISO 31700.
What features should I look for in a B2B data API for AI agents?
Focus on: verified accuracy rates (not just claimed), structured JSON response schemas that map predictably into your agent’s data model, real-time vs. batch endpoints depending on your workflow, compliance documentation for your target markets, rate limits and SLA at your expected volume, and native agent connectivity such as MCP or published webhooks.
How much do B2B data APIs cost?
Pricing varies widely. Hunter.io starts at $34/mo for email-only. Lusha starts at $37/mo (annual) with contact and company data plus buying signals. Apollo.io starts at $49/mo. People Data Labs starts at $98/mo for developer-grade enrichment. Clay starts at $149/mo but you pay underlying provider costs on top. Cognism and ZoomInfo both require annual contracts starting around $15,000/yr. Most providers offer a free tier adequate for prototyping.
Conclusion
The B2B data API you choose becomes the accuracy floor for every AI agent decision built on top of it. A wrong email address breaks a personalization. A stale title misroutes a lead. A missing direct dial kills a dialer workflow. For most teams, Lusha’s combination of 98% email accuracy, native MCP connectivity, real-time buying signals, and a free starting tier makes it the lowest-friction, highest-quality foundation for agentic GTM workflows. Apollo.io is the right trade-off for teams optimizing purely for price-per-record on email-first workflows. People Data Labs is the right choice for developers who want raw enrichment infrastructure without a GTM product layer.
The short version: start with a provider that verifies its data rather than one that claims it, and confirm your API of choice integrates natively with the agent framework you are already building on before committing to an annual contract.
