API Documentation

The Mailsfinder API lets you find and verify B2B email addresses programmatically. Integrate email finding and verification into your CRM, sales workflows, or custom applications.

link

Base URL

server.mailsfinder.com

lock

Auth

Bearer API Key

data_object

Format

JSON

api

Endpoints

4 endpoints

Authentication

All API requests require a Bearer token in the Authorization header. Get your API key from your Mailsfinder dashboard under Account → API.

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

POST

Email • Find

Find an email by name and domain.

https://server.mailsfinder.com/api/access-key/email/findEmail

Request body

Field	Required	Description
first_name	Yes	Person's first name
last_name	Yes	Person's last name
domain	Yes	Company domain

curl -X POST "https://server.mailsfinder.com/api/access-key/email/findEmail" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "first_name": "John",
  "last_name": "Doe",
  "domain": "example.com"
}'

await fetch("https://server.mailsfinder.com/api/access-key/email/findEmail", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "first_name": "John",
    "last_name": "Doe",
    "domain": "example.com"
  })
})

import requests

r = requests.post(
    "https://server.mailsfinder.com/api/access-key/email/findEmail",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json"
    },
    json={
        "first_name": "John",
        "last_name": "Doe",
        "domain": "example.com"
    }
)
print(r.json())

Response

Field	Type	Description
email	string	Found email address
status	string	Verification status (Valid, Invalid, Unknown)
confidence	number	Confidence score (0-100)
domain	string	Company domain
time	number	Processing time (ms)

200 We found the email successfully. 400 Missing required fields. 401 Not logged in. 500 Server error.

POST

Email • Find Bulk

Find emails in bulk. Send an array of objects with first_name, last_name, and domain.

https://server.mailsfinder.com/api/access-key/email/findBulkEmail

Request body

Field	Required	Description
items[]	Yes	Array of objects with first_name, last_name, domain

curl -X POST "https://server.mailsfinder.com/api/access-key/email/findBulkEmail" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '[
  {
    "domain": "example.com",
    "first_name": "John",
    "last_name": "Doe"
  },
  {
    "domain": "example.com",
    "first_name": "Jane",
    "last_name": "Smith"
  }
]'

await fetch("https://server.mailsfinder.com/api/access-key/email/findBulkEmail", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
  },
  body: JSON.stringify([
    { "domain": "example.com", "first_name": "John", "last_name": "Doe" },
    { "domain": "example.com", "first_name": "Jane", "last_name": "Smith" }
  ])
})

import requests

r = requests.post(
    "https://server.mailsfinder.com/api/access-key/email/findBulkEmail",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json"
    },
    json=[
        {"domain": "example.com", "first_name": "John", "last_name": "Doe"},
        {"domain": "example.com", "first_name": "Jane", "last_name": "Smith"}
    ]
)
print(r.json())

200 All emails were processed. 400 List is incorrect or incomplete. 401 Not logged in. 429 Too many requests at once. 500 Error processing emails.

POST

Email • Verify

Verify a single email address.

https://server.mailsfinder.com/api/access-key/email/verifyEmail

Request body

Field	Required	Description
email	Yes	Email address to verify

curl -X POST "https://server.mailsfinder.com/api/access-key/email/verifyEmail" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "email": "john.doe@example.com"
}'

await fetch("https://server.mailsfinder.com/api/access-key/email/verifyEmail", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "email": "john.doe@example.com"
  })
})

import requests

r = requests.post(
    "https://server.mailsfinder.com/api/access-key/email/verifyEmail",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json"
    },
    json={"email": "john.doe@example.com"}
)
print(r.json())

Response

Field	Type	Description
email	string	Email address verified
status	string	Verification result (Valid, Invalid, Unknown)
domain	string	Email domain
time	number	Processing time (ms)

200 Email checked successfully. 400 Email not included. 401 Not logged in. 422 Incorrect email format. 500 Mail server did not respond.

POST

Email • Verify Bulk

Verify a list of email addresses in bulk.

https://server.mailsfinder.com/api/access-key/email/verifyBulkEmail

Request body

Field	Required	Description
emails[]	Yes	Array of email address strings

curl -X POST "https://server.mailsfinder.com/api/access-key/email/verifyBulkEmail" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "emails": [
    "john.doe@example.com",
    "jane.smith@example.com"
  ]
}'

await fetch("https://server.mailsfinder.com/api/access-key/email/verifyBulkEmail", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "emails": [
      "john.doe@example.com",
      "jane.smith@example.com"
    ]
  })
})

import requests

r = requests.post(
    "https://server.mailsfinder.com/api/access-key/email/verifyBulkEmail",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json"
    },
    json={
        "emails": [
            "john.doe@example.com",
            "jane.smith@example.com"
        ]
    }
)
print(r.json())

200 All emails were checked. 400 Email list is missing or incorrect. 401 Not logged in. 429 Too many emails too fast. 500 Verification failed due to server issues.

Status Codes

Code	Meaning	Action
200	Success	Request processed. Parse the response JSON.
400	Bad Request	Check required fields. Ensure JSON is valid.
401	Unauthorized	Check your API key. Make sure it's in the Authorization header.
422	Unprocessable	Email format is invalid. Check the address.
429	Rate Limited	Too many requests. Wait and retry with backoff.
500	Server Error	Something went wrong on our side. Retry after a moment.

Rate Limits

API rate limits depend on your plan. If you hit a rate limit, you'll receive a 429 response. Wait and retry with exponential backoff.

Free Plan

100

credits per day

Pro Plan

10,000

credits per month

Agency+ Plans

100,000+

credits per month

Need higher limits? Talk to sales for custom API access.

API Documentation

Authentication

Email • Find

Request body

Response

Email • Find Bulk

Request body

Email • Verify

Request body

Response

Email • Verify Bulk

Request body

Status Codes

Rate Limits

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