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Hunter API

Give your agents access to Hunter API. Bring your own Hunter key, or skip the signup and pay per call from your Composio balance with Composio Instant.

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Hunter

Instant

Hunter is an email marketing platform for lead generation and contact data enrichment. It helps you quickly find and verify professional email addresses to boost outreach.

39 Tools

COMPOSIO INSTANT

What is Composio Instant?

Composio Instant lets your agent use paid APIs like Hunter without a separate account or API key for each one. New accounts start with $2 of free credit.

No Hunter account or key

Your agent calls Hunter through Composio, so there is nothing to sign up for, store, or rotate.

Pay per call, at cost

$0.004 per billed company enrichment, paid from your Composio balance with zero markup.

Works in any agent

Claude, ChatGPT, Cursor, and other MCP clients, or your own code with the Composio SDK.

Works with your apps

Use Hunter with Gmail, Slack, Google Sheets, and 1,700+ other apps you connect.

AI ASSISTANTS

Connect the Hunter API to your AI assistant

Use Hunter from the AI assistant you already work in. Connect Composio once, then paste the prompt.

1
Open the Connectors menu
Use the button to open Claude's Add connector dialog with Composio filled in. Or click + in the message box, then Connectors, Add connector and Add custom connector.
Add Composio to Claude
2
Add the Composio MCP server
Name it Composio, paste the MCP server URL and click Add.
https://connect.composio.dev/mcp
3
Authorize in your browser
A browser window opens. Sign in to Composio to approve the connection.
4
Paste the prompt
Start a new chat and paste the prompt. Claude runs the call on Composio Instant.

1
Install the Composio plugin
Open Composio's plugin page in ChatGPT and click Install. Sign in to ChatGPT first if it asks.
Install in ChatGPT
2
Authorize in your browser
Connect the plugin, then sign in to Composio to approve the connection.
3
Turn on Composio in your chat
In a new chat, click +, then More, and select Composio.
4
Paste the prompt
Paste the prompt into that chat. ChatGPT runs the call on Composio Instant.

1
Install the Composio plugin
Open Composio in the Cursor marketplace, click Install Composio Plugin for Cursor and approve the connection in your browser.
Install in Cursor
2
Paste the prompt
Open the Agent chat and paste the prompt. Cursor runs the call on Composio Instant.

1
Add the Composio plugin
Open Composio's listing on x.ai and click Add to Grok Bot. When Grok Bot opens the plugin, click Add.
Add to Grok Bot
2
Authenticate
Go to Installed, open Composio and click Authenticate. Sign in to Composio and click Authorize.
3
Paste the prompt
Paste the prompt into your bot's chat. Grok Bot runs the call on Composio Instant.

1
Paste the setup prompt
Copy this into your Hermes chat. Hermes adds the Composio MCP server for you.
Set up Composio from composio.dev/hermes
2
Authorize in your browser
A browser window opens. Sign in to Composio to approve the connection.
3
Paste the prompt
Start a new chat and paste the prompt. Hermes runs the call on Composio Instant.

ClaudeNew chat

Paste this prompt

Use Hunter through Composio Instant to retrieve company enrichment information for microsoft.com. Return the company information in a brief summary.

What success looks like

HUNTER_COMPANY_ENRICHMENT

Your assistant runs Hunter and replies with a brief summary of company information for Microsoft.

Runs on Composio Instant

SDK

Use the Hunter API in your code

Call Hunter from your own agent with the Composio SDK. Four steps and one tool call.

1
Set up Composio
Turn on Instant Toolkits in your project settings and check your prepaid balance in Billing. Then set your API key.
export COMPOSIO_API_KEY="your_composio_api_key"
2
Install the SDK
The Python SDK needs Python 3.11 through 3.15.
The TypeScript SDK is ESM-only and needs Node.js 22.22.3 or newer.
pip install composio
npm install @composio/core
3
Run the call
Create a session that keeps Instant to this toolkit and reports the charge, then run the tool on the Instant account.
HUNTER_COMPANY_ENRICHMENT
4
Read the response
When the call runs on Instant, the response includes its charge: the amount as an exact USD decimal string, the currency and charged_by.

agent.py

from composio import Composio

composio = Composio()

session = composio.sessions.create(
    user_id="user_123",
    toolkits=["hunter"],
    instant={
        "toolkits": {"enable": ["hunter"]},
        "return_instant_charge": True,
    },
)

result = session.execute(
    "HUNTER_COMPANY_ENRICHMENT",
    arguments={
        "domain": "microsoft.com",
    },
    account="instant_account",
)
print(result)
print("Instant charge:", result.instant_charge)

agent.ts

import { Composio } from "@composio/core";

const composio = new Composio();

const session = await composio.create("user_123", {
  toolkits: ["hunter"],
  instant: {
    toolkits: { enable: ["hunter"] },
    returnInstantCharge: true,
  },
});

const result = await session.execute(
  "HUNTER_COMPANY_ENRICHMENT",
  {
    "domain": "microsoft.com"
  },
  { account: "instant_account" },
);
console.log(result);
console.log("Instant charge:", result.instantCharge);

response

{
  "data": "<company enrichment information>",
  "error": null,
  "successful": true,
  "instant_charge": {
    "amount": "<usd amount>",
    "currency": "USD",
    "charged_by": "<provider>"
  }
}

TOOLS

Available Hunter API tools

8 Hunter tools run on Instant, priced per call with no Hunter key. Tools marked Your key need your own Hunter account.

Action	Tool slug	What it does	Availability
Discover Companies	HUNTER_DISCOVER_COMPANIES	Find companies that match filters or a natural language query.	Instant$0 per request
Enrich Company	HUNTER_COMPANY_ENRICHMENT	Get company information from its domain.	Instant$0.004 per billed company enrichment40% off
Search Domain	HUNTER_DOMAIN_SEARCH	Find email addresses and related metadata for a domain or company.	Instant$0.024 per search returning 1-10 emails; free if none found.50% off
Find Email	HUNTER_EMAIL_FINDER	Find the most likely email address for a person at a company.	Instant$0.024 per email found50% off
Verify Email	HUNTER_EMAIL_VERIFIER	Check whether an email address can receive messages.	Instant$0.012 per billed email verification50% off
Enrich Person and Company	HUNTER_COMBINED_ENRICHMENT	Get person and company details from an email address or LinkedIn handle.	Instant$0.004 per billed combined enrichment40% off
Email Count	HUNTER_EMAIL_COUNT	Tool to get the total number of email addresses Hunter has for a domain or company with breakdowns by type, department, and seniority.	Instant$0 per request
People Enrichment	HUNTER_PEOPLE_ENRICHMENT	Enrich a person by email address or LinkedIn handle with available details such as name, job title, and social handles.	Instant$0.004 per billed person enrichment40% off
Upsert Lead	HUNTER_UPSERT_LEAD	Create or update a lead by email in one call.	Your key
List Leads	HUNTER_LIST_LEADS	Retrieve leads saved in your account, with optional filters.	Your key

Instant prices are Hunter's list prices with 0% markup, paid from your Composio balance and updated every hour. Instant calls also count toward your plan's tool calls. See all plans on the pricing page.

USE CASES

Hunter API use cases and example prompts

Copy a prompt into your agent. Each one uses Hunter with apps you connect through Composio.

Find payroll software prospects
Use Hunter to find companies that sell payroll software to mid-sized businesses. Add the matching results to my Payroll Prospects sheet in Google Sheets, then post a summary in Slack's #sales channel.
Apps used: Hunter, Google Sheets, Slack
Create an account research page
Use Hunter to get company information for acme.com. Save the findings in an Acme account research page in Notion, with a short summary for our sales team.
Apps used: Hunter, Notion
Prepare an account outreach draft
Use Hunter to get company information for acme.com and find generic role inboxes for the domain. Update the Acme company record in HubSpot with the findings, then draft a Gmail message to the sales inbox Hunter finds that uses a relevant company detail as the reason for reaching out.
Apps used: Hunter, HubSpot, Gmail
Check prospect email addresses
Use Hunter to check whether each email in my Prospect Queue sheet in Google Sheets can receive messages. Add Hunter's result beside each address, then post a Slack update in #sales naming the records that need review.
Apps used: Hunter, Google Sheets, Slack

TROUBLESHOOTING

Hunter API troubleshooting

Still stuck? The Instant tools docs cover limits, charges and session settings.

Set the department parameter in HUNTER_DOMAIN_SEARCH to filter by one or more departments.

Set industry_include and industry_exclude in HUNTER_DISCOVER_COMPANIES to filter the results.

Check its availability in the tools table. If it runs on Instant, check that Instant Toolkits is on for your project, your session allows the action and you use the latest toolkit version.

Your Composio balance is empty. Add funds in Billing if your plan supports it, or connect your own Hunter account.

Check credential_source and instant_charge in the Composio execution log.

COMPOSIO INSTANT

Other tools on Instant

These tools also run on Composio Instant and use the same Composio balance.

Toolkit marketplace

Ahrefs

Api KeyOauth2

Ahrefs is an SEO and marketing platform for site audits, keyword research, and competitor insights. It helps you improve search rankings and drive organic traffic.

ScrapeCreators

Api Key

ScrapeCreators is a scraping service that extracts public profiles, posts, videos, comments, ads, and other content from social platforms. Use it to quickly collect structured public social data for analysis, monitoring, and content research.

Zerobounce

Api Key

ZeroBounce is an email validation and deliverability platform that detects invalid or risky email addresses. It helps businesses improve email marketing results by ensuring emails actually reach real people.

Firecrawl

Api Key

Firecrawl automates large-scale web crawling and data extraction. It helps organizations efficiently gather, index, and analyze content from online sources.

Start with Hunter.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Hunter tool your agent needs.Free to start.

Start building

Hunter API

What is Composio Instant?

No Hunter account or key

Pay per call, at cost

Works in any agent

Works with your apps

Connect the Hunter API to your AI assistant

Open the Connectors menu

Add the Composio MCP server

Authorize in your browser

Paste the prompt

Install the Composio plugin

Authorize in your browser

Turn on Composio in your chat

Paste the prompt

Install the Composio plugin

Paste the prompt

Add the Composio plugin

Authenticate

Paste the prompt

Paste the setup prompt

Authorize in your browser

Paste the prompt

Use the Hunter API in your code

Set up Composio

Install the SDK

Run the call

Read the response

Available Hunter API tools

Hunter API use cases and example prompts

Find payroll software prospects

Create an account research page

Prepare an account outreach draft

Check prospect email addresses

Hunter API troubleshooting

Domain search returns addresses from the wrong departments

Company discovery returns firms outside the target industries

An action asks you to connect Hunter

You get HTTP 402 with Metering_WalletBalanceExhausted

You're not sure which account was charged

Other tools on Instant

Ahrefs

ScrapeCreators

Zerobounce

Firecrawl

Start with Hunter.It takes 30 seconds.