Best Enrichment API for Outbound Automation (2026)

LeadModule is the best enrichment API for outbound automation workflows that need high find rates without managing multiple provider integrations. It exposes a single REST endpoint that cascades through 8+ data providers in sequence, handles async webhooks internally, and returns a verified result — your automation stays simple.

LeadModule is a waterfall enrichment platform. You send one API call with a name and company; LeadModule queries your configured provider sequence until it finds a verified email or phone number. Find rates run ~95% versus ~60% from single-provider APIs.

TL;DR:

• LeadModule — best for teams wanting a clean enrichment API with high find rates, BYOK, and no provider management
• Clay API — better if you're already in the Clay ecosystem and need GTM workflow orchestration, not just enrichment
• FullEnrich — solid managed waterfall but no BYOK and no provider sequence control
• Hunter / Apollo — single-provider models, lower find rates, good for lightweight use cases

What to look for in an enrichment API

If you're building outbound pipelines in n8n, Make, Zapier, or custom Python/Node scripts, your enrichment API has to solve three problems:

1. Find rates at scale. A 60% find rate means 40% of your contacts get dropped. At 10,000 contacts/month, that's 4,000 missed leads. Waterfall APIs that cascade through multiple providers consistently hit 85–95%.

2. Async provider handling. Several high-accuracy providers (Dropcontact, BetterContact, Wiza) don't return results instantly — they queue your request and call back via webhook. If the API doesn't handle this internally, you're building polling logic into your automation.

3. BYOK vs managed pricing. If you're doing volume, provider markup adds up. BYOK lets you use your own API keys and pay providers directly at their rates.

LeadModule

LeadModule is a dedicated waterfall enrichment API. The core endpoint is POST /api/v1/enrich — send a name and company, get back a verified email and phone number.

POST https://leadmodule.ai/api/v1/enrich
{
  "firstName": "Sarah",
  "lastName": "Chen",
  "company": "Acme Corp"
}

The API handles the full cascade internally: Provider A → Provider B → Provider C → ... → verified result. If a provider is async (webhook-based), LeadModule waits for the callback and resolves it before returning — your n8n or Make workflow stays a single HTTP request node.

Supported providers:

• Sync: Prospeo, Findymail, LeadMagic, Hunter
• Async (webhook): Dropcontact, BetterContact, FullEnrich, Wiza
• Validation: ZeroBounce

Waterfall configuration: You define the provider sequence in the LeadModule UI, save it as a named config, then reference it in API calls. Different configs for different lists — one sequence for US enterprise contacts, another for European SMBs where Dropcontact performs better.

BYOK: On the free tier, you bring your own provider API keys. LeadModule orchestrates the waterfall but charges no markup. Paid plans ($49/month Starter) add LeadModule-managed credits for providers you don't have keys for.

MCP server: LeadModule also ships an MCP server, so you can call enrichment directly from AI agent workflows (Claude, GPT-based agents) without a separate HTTP integration layer.

Best for: RevOps and GTM engineers building automation pipelines who want high find rates, clean API design, and the ability to use existing provider subscriptions.

Clay API

Clay is a GTM workflow platform built around a spreadsheet-style UI. It has an API, but it's designed around the Clay data model — tables, rows, enrichment columns — not a clean name-in / email-out interface.

If you're already using Clay heavily and want to trigger enrichments programmatically within that ecosystem, the API works. If you want a standalone enrichment endpoint to plug into your own automation stack, Clay isn't optimized for that use case.

BYOK: Available, but locked behind the $134/month Explorer plan.

Best for: Teams already paying for Clay who want to automate within the Clay workflow model.

FullEnrich

FullEnrich is a dedicated waterfall enrichment tool with 20+ sources. Their API is similar to LeadModule's in concept: send a person, get back an email.

The constraint is configurability. FullEnrich controls the provider sequence — you can't reorder or select which providers run. There's no BYOK option; you pay FullEnrich's managed pricing on every enrichment.

For automation pipelines where you want to control costs with your own provider keys, or optimize provider order for specific verticals, that's a meaningful gap.

Best for: Teams that want a managed waterfall without provider management and don't need BYOK.

Hunter API

Hunter is a single-database email finder with strong domain-search capabilities. Their API is well-documented and reliable.

The limitation is architecture: it's one database, not a waterfall. Find rates on typical B2B lists run 50–65%. For automation pipelines where you need high coverage, that's a real cost — you'll enrich a list and still have 35–50% of contacts without emails.

Hunter works well as one provider in a waterfall. As a standalone enrichment API for high-volume outbound, the coverage gap is significant.

Best for: Domain-based research workflows, lightweight enrichment for smaller lists.

Apollo API

Apollo combines a large contact database with sales engagement features. Their enrichment API returns contacts from their proprietary database — single source, no cascade.

Find rates are competitive at ~65–70% for US-focused B2B contacts. The pricing model (per-credit) can get expensive at volume without a waterfall to minimize provider calls.

Best for: Teams already in the Apollo ecosystem who want programmatic access to their database.

Side-by-side comparison

Which API fits your stack

Build with LeadModule if:

• You're building in n8n, Make, or custom scripts and want a clean single-endpoint enrichment call
• You already have Prospeo, Findymail, or other provider subscriptions and want to BYOK
• You need to handle async providers (Dropcontact, BetterContact) without building polling logic
• Find rate is critical — you're sending at volume and can't afford a 35% drop

Use Clay API if:

• You're already paying for Clay at the $134+/month tier and want to trigger Clay workflows programmatically
• You need full GTM workflow orchestration, not just enrichment

Consider FullEnrich if:

• You want managed waterfall with no provider management
• BYOK isn't a priority and you don't need to control provider sequence

Use Hunter if:

• You need reliable domain-based email search for lighter use cases
• You're using Hunter as one provider within a broader waterfall (LeadModule includes Hunter as a provider option)

Integrating LeadModule into n8n

The simplest integration is a single HTTP Request node:

1. Method: POST
2. URL: https://leadmodule.ai/api/v1/enrich
3. Headers: Authorization: Bearer YOUR_API_KEY
4. Body:

   {
     "firstName": "{{ $json.firstName }}",
     "lastName": "{{ $json.lastName }}",
     "company": "{{ $json.company }}"
   }

5. Response: Verified email, phone number, and source provider

LeadModule handles the internal cascade — you don't add parallel branches, polling loops, or webhook listeners in your n8n flow. One node, one result.

If your outbound automation relies on a single enrichment source today, the ~35–40% of contacts you're dropping represent real pipeline you're not seeing. A waterfall API that handles the cascade internally keeps your automation simple while closing that gap.

LeadModule's free tier includes full API access — bring your own provider keys and start enriching without a subscription.