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Email Validation API Pricing: 100 Free Checks, Then Credit Packs

Published 2026-10-13

ContactLint checks email addresses and phone numbers over a simple HTTP API. The pricing fits in one sentence: your first 100 checks each month are free, and after that you buy a credit pack. No card is needed to start.

Below is the price list, the cost per check, and what a few real jobs cost, so you can budget before you write any code. All prices are in USD.

The price list

Credits do not expire. Unused credits are refundable within 14 days of purchase.

The free tier is 100 checks per key per calendar month. Unused free checks do not roll over. Paid credits only start getting used once that month's free checks are gone.

Cost per check, worked out

Here is the math, so you do not have to do it.

The 100,000 pack lands just under one tenth of a cent per check. Bigger packs are cheaper per check, but only if you actually use the checks. Buy for the volume you expect. Since credits do not expire, buying ahead for work you know is coming costs you nothing extra.

What one check gets you

One check is one API or MCP call to a validation tool. That is true whether you hit the REST endpoints directly or call the validate_email and validate_phone tools from an MCP client.

Email checks

Each email check runs:

• Practical RFC syntax validation
• MX and A record lookups via DNS-over-HTTPS
• A disposable domain list check
• Role address detection, such as admin@ and info@
• A free mail provider flag

Phone checks

Each phone check returns:

• Parsing with libphonenumber metadata
• Valid and possible flags
• Line type and region
• E.164, national, and international formats

What it does not do

ContactLint never opens an SMTP connection to the mailbox. It tells you whether an address is well formed, whether its domain has mail or address records, and whether it is disposable, a role address, or on a free mail provider. It does not confirm that a specific inbox exists or that a person will get your mail.

Carrier lookups for phone numbers are not offered today.

Keep both of those in mind when you compare prices.

What a real job costs

These examples use only the published prices and the published rate limit of 60 requests per minute per key. Each row shows the single pack that covers the job, what each check you used actually cost, and the shortest time the job could take running at the limit.

A signup form

Under 100 new contacts a month? The free tier covers you. Validate each email as it comes in and pay nothing.

A CRM export cleanup

A 4,000 row export of emails fits in one 5,000 pack for $9. You end up with about 1,000 credits left, plus your free 100 for the month. Those leftover credits stay on the balance.

Add a phone check for every row and you are at 8,000 checks. One 25,000 pack handles it for $35 and leaves 17,000 checks for later imports or an ongoing signup form.

Budget time as well as money. At 60 requests per minute, 8,000 checks take a little over two hours. Pace your script so it stays under the limit.

A large list

For 60,000 checks, one 100,000 pack runs $99 and leaves 40,000 checks for your next cleanup. At the rate limit, the run takes at least 16 hours 40 minutes. Set it up as a background job, not something you sit and watch.

Credit packs vs monthly plans

ContactLint's paid options are credit packs, not monthly plans. For a small team, that changes the bill.

A monthly plan charges you every month, whether you validate 10 addresses or 10,000. A credit pack charges you once, and you draw it down as you go. That suits work that comes in bursts: a one-time CRM cleanup, a quarterly list import, an AI agent that checks contact data now and then.

Your free 100 checks a month still apply on top of any credits you hold. Purchased credits do not expire.

Stripe processes payments, and ContactLint never sees or stores your full card number. Prices may change, but a change does not touch credits you already bought.

Refunds, limits, and errors

Refunds. Unused credits are refundable within 14 days of purchase. Buy a pack and run it against real data. If it does not fit your workflow, email support@contactlint.com within those 14 days and ask for the unused credits back. Used credits are non-refundable. The full billing and refund language is in the ContactLint terms.

Rate limit. Each key can make up to 60 requests per minute. Go over and you get a 429.

Errors you may see:

• 401: missing or invalid key.
• 402: free checks used up and no credits.
• 429: more than 60 requests per minute per key.
• 400: bad input.

If you see a 402, it is time to add credits.

Track what you have left

Call GET /v1/usage with your key. It returns the free checks used this month and your credit balance. Run it before a big batch job so you do not stall halfway through.

Send your key as Authorization: Bearer YOUR_KEY or x-api-key. Endpoints, auth headers, and a curl example are on the email and phone validation API docs.

Using an AI agent? Point any MCP client that supports streamable HTTP at https://contactlint.com/mcp with your key in the Authorization header. The tools are validate_email and validate_phone. Each tool call uses one check at the same prices as above.

The emails and phone numbers you check are processed only to return a result. They are not stored. For the details, read how ContactLint handles your data.

FAQ

How much does the ContactLint email validation API cost? The first 100 checks each month are free, and no card is required. After that you buy credit packs: 5,000 checks for $9, 25,000 for $35, or 100,000 for $99. The paid options are credit packs, not monthly plans. Each MCP tool call uses one check.

What does one check cost on each pack? Divide the price by the checks. The 5,000 pack works out to $0.0018 per check. The 25,000 pack is $0.0014 per check. The 100,000 pack is $0.00099 per check, which is just under one tenth of a cent. Bigger packs cost less per check, so buy the size you expect to use.

Can I get a refund on unused credits? Yes. Unused credits are refundable within 14 days of purchase, which gives you two weeks to run the API against real signups or a CRM export. If the results do not fit your workflow, email support@contactlint.com to ask for a refund. Used credits are non-refundable.

What happens when the free checks run out? The API returns a 402 error when your free checks for the month are used up and you have no credits. Add a credit pack to keep validating. You can call GET /v1/usage at any time to see free checks used this month and your credit balance.

Is there a rate limit? Yes. Each key can make up to 60 requests per minute. Go past that and the API returns a 429 error. For most signup forms that is enough. For a large CRM cleanup, pace your batch job to stay under 60 a minute, and check your credit balance before you start.

Does the free plan need a credit card? No. The free key gives you 100 checks per month and no card is required. Sign up with an email address, and the key is shown once on the next page, so copy it right away. No email is sent. Disposable addresses are not accepted at signup.

Start with 100 free checks

Try it on your own data before you spend a dollar. Get a free email validation API key. You get 100 checks per month, no card required. Your key is shown once, so save it somewhere safe.

Need more volume? Buy credits. Credits do not expire, and unused credits are refundable within 14 days of purchase.

Billing questions: support@contactlint.com

Get a free API key. 100 checks per month, no card required.