POST/v1/email/format

Email Pattern API

Discover a company's most common email address patterns.

Return the email address patterns a company uses, each with the percentage of known addresses that follow it — {first}, {first}.{last}, {f}{last}, and so on. Use the dominant pattern to construct or validate emails for contacts you can't find directly.

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Try it live

Fill in the fields and hit Run to see a real response.

POST/v1/email/formatformat$0.01/call

Response

Example response — hit "Send Request" to see a live result

{
  "data": {
    "patterns": [
      {
        "pattern": "{last}",
        "percentage": 2
      },
      {
        "pattern": "{first}.{last}",
        "percentage": 9
      },
      {
        "pattern": "{f}{l}",
        "percentage": 2
      },
      {
        "pattern": "{first}",
        "percentage": 64
      },
      {
        "pattern": "{f}{last}",
        "percentage": 23
      }
    ]
  },
  "ok": true
}

Features

✓

Ranked pattern list

Every known format is returned with the share of the company's addresses that use it, so the dominant pattern is obvious at a glance.

✓

Standard placeholder syntax

Patterns use clear tokens like {first}, {last}, {f}, and {l}, ready to plug names into and generate candidate emails.

✓

Guess emails you can't find

When a contact isn't in the index, the company's top pattern plus a name gives you a high-probability address to verify.

✓

One-cent lookups

At $0.01 per domain it's cheap enough to run across an entire prospect list to pre-compute email formats.

Use cases

Email Construction

Build likely addresses for hard-to-find contacts from the company's dominant pattern and a known name.

Address Validation

Confirm that a guessed email matches how the company actually formats its addresses before verifying.

Bulk Prospecting

Pre-compute email formats for a list of target domains to speed up downstream finding.

Quick start

Copy this snippet and start making calls.

const res = await fetch('https://api.yepapi.com/v1/email/format', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "domain": "stripe.com"
  }),
});
const data = await res.json();
console.log(data);

The email pattern API — a company's address format

The Email Pattern API returns the address formats a company uses, ranked by how many of its known emails follow each one. With the dominant pattern and a person's name you can construct a high-probability email for any contact that isn't already indexed.

At $0.01 per domain with $5 of free credit and no minimums, it's cheap enough to pre-compute formats across a whole prospect list. Pair it with the Email Verifier to confirm each constructed address before sending.

Start making API calls in 30 seconds

$5 free credit on signup. No credit card required. Pay per call.

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Frequently asked questions

Each API call costs $0.01. No monthly minimums or subscriptions — you only pay for what you use.

Sign up for a free API key, then send a POST request to /v1/email/format. Check the code example above for a ready-to-use snippet in JavaScript, cURL, or Python.

YepAPI bundles SEO, AI, and web scraping APIs under one key with no monthly minimums. You get lower per-call pricing, a unified dashboard, and one billing account instead of managing multiple providers.