# Mails.so review (2026): is it worth €48 a month? > Email validation API and list checker with flat monthly plans Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA. Mails.so is an email validation service with a web checker, list upload and an API. Paid plans are monthly and all include API access, list validation, an email finder and Mailchimp and HubSpot integrations. The pricing section sits on its homepage and is shown in euros. - **Category:** Email Verification & Deliverability - **Made by:** Mails, Inc. - **Website:** https://mails.so - **Runs on:** Web - **Who should skip it:** Watch out: the 90% first-month discount lasts one month, then the plan renews in full. - **Facts last checked:** Nov 13, 2026 ## Pricing As of Nov 13, 2026, Mails.so is a paid product with a free trial, starting at €48 per month for 10,000 validations, shown in euros. - **Pricing model:** Free trial - **Free plan:** None. - **Free trial:** 50 free credits on sign-up, no credit card required. | Plan | Price | What you get | | --- | --- | --- | | Pro | €48 per month for 10,000 validations | First month €4.80 (90% off). 5 concurrent validations; top-ups at €0.005 per validation. | | Business | €98 per month for 50,000 validations | First month €9.80 (90% off). 5 concurrent validations; top-ups at €0.002 per validation. | | Unlimited | €498 per month for unlimited validations | First month €49.80 (90% off). 10 concurrent validations. | Read from https://mails.so/ on Nov 13, 2026. Prices change, so confirm with Mails.so before buying. ## Ways to pay less - **90% off the first month** (Other savings): The homepage shows each paid plan at 90% off for the first month, then at full price. No end date is shown. Source: https://mails.so/ ## Key features - **List validation:** Upload a list to check its addresses, or paste single addresses into the checker on the homepage. - **Validation API:** Every paid plan includes API access, for checking addresses at signup or inside other software. - **Email finder:** An email finder is included on all three paid plans. - **Mailchimp and HubSpot integrations:** Listed on every paid plan for cleaning lists held in those platforms. - **Top-ups:** Extra validations can be bought at any time on Pro and Business at a stated per-validation rate. ## Good for - Developers and teams wanting a predictable monthly validation fee - Small lists, using the 50 free credits first - High-volume senders considering the unlimited plan ## Worth knowing - Prices were read in euros; a US dollar view could not be read, so the dollar price is unconfirmed. - The 90% first-month discount applies to the first month only; the plan then renews at full price. - The free allowance is a one-time 50 credits, not a monthly free plan. - Only the three paid plans were listed; there is no separate pay-as-you-go pack on the page. ## ToolGPA grades **GPA: 2.2 out of 4**, graded Nov 13, 2026. Mails.so validates addresses by list or API on flat monthly plans, from €48 for 10,000. The first month is 90% off and then renews at full price, the free allowance is a one-time 50 credits, and we only saw euro prices. - **Value for money: C.** €48 a month for 10,000 validations, which is near the category's $49 dearer quarter once converted. The dollar price is unconfirmed. - **Free plan and trial: C.** 50 free credits on sign-up with no card, once. No monthly free plan. - **Features: C.** List validation, an API and an email finder. Only the three paid plans are listed, with no pay-as-you-go pack. - **Ease of use: C.** No store rating on record. You upload lists or use the API. - **Platforms and integrations: B.** Web and API with Mailchimp and HubSpot links. No apps. These are ToolGPA's own grades. Graded from this listing, whose facts were read from Mails.so's own pages on 13 November 2026. Not based on using the product, and shorter than our full reviews. ## Where it stands among email verification and deliverability tools - Mails.so's GPA of 2.2 is higher than 23 of the 61 other email verification and deliverability tools we grade, and level with 13. - It stands best on platforms and integrations (B, above 28 of 61) and worst on features (C, above 0). - Its paid plans start at about $53.63 a month, against a middle price of $21.50 for the category: 34 of the 43 others that charge start lower. - On features, ease of use and platforms it scores 2.3 out of 4. 8 tools score higher and cost less. The category's chart of price against score: https://toolgpa.com/charts/email-deliverability ## Keep it, or make your own? **Keep it.** Nothing Mails.so does is plain enough to make in a weekend. The 2 things listed below take a company. It costs $643.51 a year. - You could not: Checking that an address exists without writing to it. - You could not: It plugs into other products, Mailchimp and HubSpot among them, and has an API. A judgement by ToolGPA from this listing, by rules that are the same for every tool. Nothing was built to test it. ## Works with Mailchimp, HubSpot **Tags:** Email verification, Public API ## Alternatives - [ZeroBounce](https://toolgpa.com/tools/zerobounce): Email list verification with warm-up and DMARC monitoring in one plan. [Compare](https://toolgpa.com/compare/mails-so-vs-zerobounce) - [NeverBounce](https://toolgpa.com/tools/neverbounce): Email list cleaning and real-time verification, now part of ZoomInfo. [Compare](https://toolgpa.com/compare/mails-so-vs-neverbounce) - [Emailable](https://toolgpa.com/tools/emailable): Email list verification with inbox reports and blacklist monitoring. [Compare](https://toolgpa.com/compare/emailable-vs-mails-so) - [MillionVerifier](https://toolgpa.com/tools/millionverifier): Low-cost bulk email verification with credits that never expire. [Compare](https://toolgpa.com/compare/mails-so-vs-millionverifier) - [Reacher](https://toolgpa.com/tools/reacher): Open-source email verification engine with an HTTP backend. [Compare](https://toolgpa.com/compare/mails-so-vs-reacher) ## Sources The prices, plans, platforms and features above were read from these pages on Nov 13, 2026: - https://mails.so/ - https://mails.so/signup Page: https://toolgpa.com/tools/mails-so Listed by ToolGPA (toolgpa.com).