Is There a Free Email Verification API? What Is Free and What Is Not

There is no free email verification API on SimpleVerifier. The API is on paid plans: Pro includes 10,000 API calls a month, and Starter has no API access. What is free is the website: 100 checks with a Google sign-in and no card, and a free email checker with no account at all. If you want a free API key specifically, a few other vendors give one, and we list them below with the dates we read them.

Better to say this up front than have you find out after reading our docs.

What is free on SimpleVerifier

What	Where	Limit
100 checks	The verify page, Google sign-in, no card	One time per account
Single-address check	Free email checker, no account	Five a minute
Whole-file checks that need no mailbox lookup	No-signup tools	Syntax, duplicates, dead domains

Free checks use the same mailbox check as the paid plans, and results come back as valid, risky or invalid with a reason. The same three labels appear in the API response, so running your first hundred addresses through the web app shows you exactly what your code will need to handle.

What is on paid plans

The API sits on paid plans. As of this post:

• Pro, $39 a month, includes 10,000 API calls a month, then $1.50 per 1,000. The first 100,000 checks a month on lists and CSVs run at full speed, then slower, never cut off.
• Starter, $9 a month, is 2,500 emails a month for lists and single checks on the site and has no API access.
• Each key can make 120 calls a minute.

Pricing has the current numbers, and the quickstart shows a call in curl, Node and Python. For the monthly cost of a signup-form integration, see what an email verification API costs per month.

Why verification APIs are rarely free

An API call is not a database lookup. A real mailbox check opens a connection to the recipient's mail server, asks whether it would accept the address, and waits for the answer. That takes seconds and uses sending infrastructure that mail providers must keep trusting. Calls from code also arrive in bursts, and signup forms attract bots who will happily use a free endpoint to test stolen address lists.

For those reasons most vendors that offer free API access limit it: a small number of credits, a trial period, or a rate cap. A free API with no limit would be a gift to abusers, and it would not last.

Vendors that include API access in free credits

Some vendors say their free credits work through the API. These come from the vendors' own pages, as recorded in our comparison data. Confirm before you build on any of them.

Vendor	Free allowance as published	Checked
VeriMails	100 free credits at signup with full API access, no card	5 Nov 2026
SafetyMails	100 free email validation credits and a 15-day real-time API trial at signup	5 Nov 2026
Email Verifier API	100 free credits at signup, no card	5 Nov 2026
Emails Checker	100 free credits at signup, no card	5 Nov 2026
Reoon	20 verifications a day, plus 100 instant credits at sign-up	30 Oct 2026
Hunter	50 credits a month on the Free plan (a verification costs 0.5 credits)	23 Oct 2026

Not every row above says outright that the free credits work through the API. VeriMails and SafetyMails do. For the others, read the vendor's pricing and docs pages before you plan around it. A free allowance on the website and a free allowance on the API are often different things.

How to try an API without paying

If you are a developer deciding whether to integrate, here is a path that costs nothing:

1. Read the docs first. The API reference and quickstart show the request, the response fields and the error codes without a key.
2. Run a sample through the web app. Sign in at /login?callbackUrl=/verify, paste fifty addresses you know the answer to and look at the labels. Valid, risky, invalid and the reason are what your code will receive.
3. Decide how your code treats risky. The usual choices: accept on signup but flag, accept and send a confirmation email, or block. The free checks are a cheap way to see how many of your real addresses fall into each bucket.
4. Test the shape of the integration against a vendor with free API credits if you want to write code before you pay anyone. Swapping the endpoint later is a small change if you keep the verifier call behind one function.
5. Pay when you ship. Pro is monthly and cancels anytime, so a launch-month subscription is a small commitment.

Do you even need an API?

A lot of "free email verification API" searches come from people who need to clean a list, not integrate with an app. If the job is a file, the API is the wrong tool:

• A CSV upload handles up to 100,000 rows on Pro with no code.
• A Google Sheets function can call the API from a column; see the custom function post if you want that and are already on a paid plan.
• The free checker is enough for one-off lookups.

The API makes sense when verification has to happen without a person pressing a button: at signup, on form submit, on a nightly import. If that is you, the call volume is probably small, and 10,000 a month covers many signup flows. For example, a form that checks once per signup covers 10,000 signups a month before the overage rate applies.

What to check in any free API tier

• Is the free credit usable through the API, or only in the dashboard?
• What is the rate limit? Signup forms need a response in a second or two. Ask what the response time is when the mail server is slow.
• What does the API return for addresses it cannot confirm? A boolean "valid" hides the cases that cause bounces. Look for a third state.
• What does a timeout look like? Your form should still work when the verifier is slow or down. Fail open, and verify later.
• Is there a key or secret in the browser? Call the API from your server, never from client-side code.

When paying makes sense

Pay for an API when verification is part of your product or signup flow and you want predictable cost. The comparison that matters is per-call price against how many calls you make. Some vendors sell a pack of credits that never expire, which suits a low and uneven call volume. A flat monthly plan suits a steady one. Our own overage rate is $1.50 per 1,000 calls past the 10,000 included on Pro, which is worth putting beside any other vendor's per-1,000 price using their pricing page.

If you also verify lists, Pro covers both: lists at full speed for the first 100,000 checks a month, and the API calls on top. See Pro on the pricing page.

Bottom line

SimpleVerifier's API is a paid feature, so we will not call it free. The free parts are the 100 checks on the website and the single-address checker with no account, and they run the same mailbox check. If you need a free API key to prototype with, use the vendors in the table, read their docs on whether free credits cover API calls, and keep your integration behind a small function so you can switch later.