MailNail Terms of Service

Version 1.0. Effective 2026-10-18.

These terms are the contract between you and MailNail. They cover the website at mailnail.com, the app at app.mailnail.com, our mail servers, the API, the MCP server and the command-line tool. Together we call them "MailNail".

1. Who we are

MailNail is run by Matyáš Černý, a Czech sole trader registered in the Czech trade register, IČO 10751084. His address is Janáčkovo nábřeží 1075/27, 150 00 Praha 5, Czech Republic. He is "we" and "us" in these terms. Write to support@mailnail.com about anything in these terms.

When MailNail s.r.o. is incorporated, it takes over these terms. We tell you before that happens.

2. The agreement

You accept these terms when you tick the box at signup, or when your organization signs an order that refers to them. If you do not agree, do not use MailNail.

If you accept for an organization, you confirm that you can bind it. "You" then means the organization. The people it lets into its workspace must follow these terms too.

These documents are part of the agreement:

• the privacy policy, which says what data we process and why
• the data processing agreement, for team workspaces
• the subprocessor list
• any order you sign with us

An order wins over these terms for its own subject. The data processing agreement wins on personal data in a team workspace.

3. Who can use MailNail

You must be 16 or older. You can use MailNail for yourself or for an organization.

A personal workspace on the free plan is for personal use. If you use MailNail for a business or other commercial work, you need a paid plan. A free team lets you try the shared features before you pay.

4. Your account

You sign in with a passkey. Keep your devices and your recovery details safe. If you lose all of them, we may not be able to give you your account back.

You are responsible for what happens in your account. This includes what your rules, workflows and agent tokens do. It does not include what happens because we broke these terms.

Tell us at once at support@mailnail.com if you think someone else has access to your account.

5. What MailNail does

MailNail brings a company's mail into one place and uses AI to do the repeated work in it. Its main parts are:

• Mailboxes. Connect a Gmail, Google Workspace, Outlook, Microsoft 365 or other IMAP mailbox. Or let us host addresses on your own domain or at mailnail.com.
• AI features. Search, chat, writing help, tags, and facts drawn from mail and attachments.
• Rules and agents. Workflows that act on mail, and agents you connect through the API, the MCP server or the command-line tool.
• Sending. Mail from your mailboxes, mail from your code, and campaigns from your domain.
• The work around the mail. Files, documents, calendars and reminders.

Your plan decides which parts you get. Settings → Plan and your order list them. We describe each feature in the app.

6. Mailboxes you connect

Your permission. When you connect a mailbox, you allow us to sync it, keep a copy and index it. You also allow us to use it for the features you or your workspace switch on. These features include AI processing and the actions you or your rules ask for. Disconnecting the mailbox ends this permission.

Your authority. You confirm that the mailbox is yours, or that its owner allowed you to connect it. Connecting it must not break your contract with the mail provider.

Work mailboxes. If your employer gives you the mailbox, your employer's rules apply to it. Connect it only if your employer allows it. The mail in it can hold data of your employer and its customers. Do not share it with agents or AI providers your employer does not allow. Your employer can ask you to disconnect the mailbox, and its admin can block MailNail. If that happens, we are not in breach of these terms.

The provider's terms. Your mail provider's own terms still apply to you. If the provider stops our access or changes its service, the features for that mailbox can stop. That is not a breach of these terms by us.

Google. MailNail's use and transfer to any other app of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements. The privacy policy says what this means for your data.

Removing our access. You can disconnect a mailbox in the app at any time. You can also remove our access at the provider: for Google at https://myaccount.google.com/permissions, and for Microsoft at https://account.live.com/consent/Manage or https://myapps.microsoft.com.

Sending limits. Mail sent from a connected mailbox counts against that provider's sending limits. Do not use a connected mailbox to send bulk or unsolicited mail.

7. AI features and agents

AI works for you. The AI answers when you ask it. It acts on your mail only when you, or a rule your workspace set, asks it to.

A person approves what leaves. Mail an agent writes waits for a person to approve it. A workspace can let a rule send without approval. The workspace is then responsible for that mail as if a person had sent it.

Check what the AI gives you. AI can be wrong, incomplete or out of date. Check figures, dates, amounts and documents before you rely on them. MailNail gives no legal, tax or financial advice.

We say when it is AI. We tell you when you deal with an AI, unless it is obvious.

Your mail does not train AI for others. We do not use your content to train AI models that serve other customers, and neither does our AI provider. Rules and examples drawn from your workspace stay in your workspace.

Your own AI provider. A workspace can connect its own OpenAI, Anthropic or Google account. That provider then processes the data under its own terms, and you pay it directly. Use a paid account whose terms forbid training on your data.

Roles. MailNail provides the AI features. Your workspace decides how to use them. Do not use them for anything the EU AI Act forbids, for example to read the emotions of your staff.

8. Agent tokens, the API and the MCP server

An agent token lets software you choose, such as an AI agent, work with your mail.

• You set the reach. A token reaches only the mailboxes and actions you pick. Picking a mailbox for a token is your consent to share its mail with that software.
• Your agent's provider sees what it reads. If your agent runs on another company's AI model, that company receives the mail your agent reads, under its own terms.
• What an agent does counts as yours. An action an agent takes within the token's reach counts as your action under these terms.
• Keep the restrictions with the data. Mail from a Google or Microsoft mailbox may serve only you. Do not let an agent use it for ads, sell it, or use it to train AI models for others.
• Everything is logged. You can read every call a token made in Settings → Agents.
• You can revoke a token at any time. Revoking stops future calls. It cannot recall what an agent already read.

Keep tokens secret. Do not share them, and do not go past the rate limits we publish.

9. Mail sent through MailNail

Your domain. You can let us receive and send mail for a domain you control. You publish the DNS records at your own DNS provider. Connect only a domain you control. If you leave, remove our records.

Rules for all mail you send. Send only mail people asked for. Do not forge who you are. Do not send malware, phishing or fraud.

Campaigns and mail from code. You are the sender and you decide who receives your mail. You need each recipient's consent where the law requires it. Every campaign carries an unsubscribe link, and you must honor each unsubscribe.

Our safety checks. We may delay, hold or refuse mail that trips our abuse checks. Section 14 says how we decide.

Hosted mail. When we host your mailbox, we carry your mail like any mail provider. We keep your communications confidential and disclose them only as the privacy policy describes.

As a micro-enterprise, we do not have to follow the special contract rules for electronic communications services under Czech law (§63e of Act No. 127/2005 Coll.).

10. Your content

Your mail stays yours. You own the messages, files and other content you keep in or send through MailNail ("your content").

What you allow us to do. You allow us to store, copy, send, index and process your content. We do so only to run MailNail for you, keep it secure, back it up and fix it. This permission ends when your content is deleted, as Section 16 describes.

What we never do. We do not sell your content. We do not use it for ads. We do not use it to train AI models for others.

Your responsibility. You must have the right to keep and send your content through MailNail.

Feedback. If you send us ideas, we can use them without paying you.

11. Team workspaces

A team workspace lets an organization own mailboxes and domains and give its members access.

• The organization controls its data. For mail in a team workspace, the organization is the controller and we are its processor. The data processing agreement applies without a separate signature.
• The organization has the legal basis. It must have the right to process the mail it puts in the workspace. It must tell its people, and the people they write to, as the law requires.
• Staff mailboxes. If the organization connects mailboxes its employees use, employment law limits how it may look at their mail. In Czechia this includes §316 of the Labour Code. Following that law is the organization's duty.
• Private stays private. A member's personal mailbox stays private unless the member shares it.
• Owners and admins. They manage members, access, AI settings and billing for the workspace.

12. Plans, prices and payment

Prices. The pricing page and your order show the price of each plan, per seat and billing period. Prices for consumers include tax. A paid seat is a person who can act, send or manage on a team mailbox. Read-only members are free.

Payment. We sell through Stripe. Link, Stripe's affiliate, is the merchant of record. It takes the payment, charges the tax and appears on your statement. Its own customer terms apply to the payment.

Renewal. A paid plan renews at the end of each billing period until you cancel it. You can cancel in Settings → Plan. The cancellation takes effect at the end of the paid period.

Seats and AI credits. Seats you add are charged for the rest of the period. AI features use AI credits. Your plan includes a monthly allowance, and you can buy more.

Refunds. We do not refund part of a period, unless the law or Section 20 says otherwise. Link may refund a purchase within 60 days under its own policy.

Price changes. We tell you at least 30 days before a new price applies to you. If you do not accept it, cancel before that date.

Late payment. If a payment stays unpaid 14 days after we tell you, we can limit your workspace to reading and exporting. The limit ends when you pay.

13. Early access and changes to MailNail

MailNail is in early access. Features change, and some are marked as early access in the app. Keep your own copies of anything you cannot afford to lose. For connected mailboxes, your provider keeps the original mail.

No uptime promise. We give no service level unless your order states one. Maintenance, outages and failures at our providers can interrupt MailNail.

Changes to features. We improve and change MailNail. We do not remove a main feature of a paid plan during your paid period without your consent. If we end MailNail as a whole, we tell you at least 90 days before, and you can export your data during that time.

14. Suspension and illegal content

When we act. We may hold your mail, limit your account or suspend it in three cases: you break these terms, the law requires it, or we must stop harm to other users or our mail servers. We warn you first, unless the harm is serious and urgent, such as a spam run, malware or fraud.

How we decide. Automatic checks look at sending behavior, bounces and complaints. They can hold mail for review. Only our staff block or suspend an account.

You get our reasons. When we restrict your account or your content, we tell you what we did, why, and how to complain. We stay silent only where the law forbids notice.

Complaints. Write to support@mailnail.com within six months of our decision. A person who did not make the decision reviews it, and we answer within 30 days.

Reporting illegal content. Anyone can report content on MailNail they think is illegal, at abuse@mailnail.com. Say where the content is, why it is illegal, and who you are. We confirm receipt and tell you what we decided.

15. Moving to another provider

You can move your data to another provider or to your own systems at any time.

1. Tell us at support@mailnail.com. The switch starts on the date you give, at most 2 months later.
2. We help you move your data within 30 days of the start.
3. We keep your data available for at least 30 more days, so you can check you have it all.
4. Then we delete it.

What you can take with you. Your mail, in a format other mail apps can import. Also your contacts, files, documents, calendars, tags, rules, workflows and workspace settings. We tell you the format of each.

What stays with us. Our own code, our models, abuse records and the internal records that protect MailNail.

No switching fee. We charge nothing for a switch or an export.

Where your data sits. The subprocessor list names where each provider processes data.

16. Ending the contract

You can leave at any time. Delete your account in Settings → Data, or cancel your plan in Settings → Plan.

We can end the contract if you seriously break these terms, if you do not pay after our warning, or if the law requires it. We can also end a free plan with 30 days notice.

What happens to your data. After the contract ends, you have 30 days to export your content. Then we delete it. Copies in our backups leave within about 8 weeks. We keep billing records and other data only as long as the law requires.

These sections stay in force after the contract ends: 10, 17, 18, 19 and 21.

17. Our warranty

We provide MailNail with reasonable skill and care. If you are a business, we give no other warranty. In particular we do not promise that every mail is delivered, synced or found, or that AI answers are correct.

If you are a consumer, your statutory rights stay as Section 20 describes.

18. Our liability

If you are a business, this section limits our liability:

• We are not liable for lost profit, lost business or indirect damage.
• We are not liable for lost data you could have kept with reasonable copies of your own.
• Our total liability for all claims in a year is the greater of EUR 1,000 and what you paid us in the 12 months before the claim.

These limits do not apply to damage we cause on purpose or by gross negligence. They also do not apply to harm to life, health or other natural rights, or where the law does not let us limit liability.

19. Your duty to cover our costs

If you are a business, you cover our costs from claims by others that arise from:

• your content
• your breach of these terms
• mail sent from your account or by your agent tokens
• a domain you had no right to connect

We tell you about each claim and let you run the defense. You may not settle a claim in a way that admits fault for us without our consent.

20. Consumers

If you buy a plan as a person, and not for a company or for your own business, we treat you as a consumer. This holds even if you use MailNail for your job.

The law of your home country can give consumers rights these terms cannot take away. Where these terms conflict with those rights, your rights win.

Before you buy. Checkout shows the price for each billing period with tax. These terms say how long the contract runs and how to cancel (Section 12). You get a confirmation of your order by email.

Your right to withdraw. You can withdraw from a paid plan within 14 days of buying it, without a reason. Tell us at support@mailnail.com, or use the form below. If you asked us to start the service at once, you pay for the days you used before you withdrew. We refund the rest within 14 days, through the payment method you used.

Your data on exit. When you withdraw or leave, you can export your content for free in a common format.

Faults. If MailNail does not work as these terms and the law promise, tell us and we fix it. If we cannot fix it in a reasonable time, you can ask for a lower price or end the contract.

Changes we make. We change MailNail only for a good reason, at no extra cost to you, and we tell you before. If a change harms you more than a little, you can end the contract free of charge within 30 days.

Complaints. Write to support@mailnail.com. We answer within 30 days.

Out-of-court disputes. You can take a dispute to the Czech Trade Inspection Authority (Česká obchodní inspekce), https://adr.coi.cz.

Withdrawal form. Copy this text into an email to support@mailnail.com: "I withdraw from my contract for the MailNail plan [name], bought on [date]. Name: [name]. Account: [username]. Date: [date]."

21. Law and courts

Czech law governs these terms. The courts of the Czech Republic decide disputes, with venue at our seat. If you are a consumer, you keep the protection of the law of your home country. You can also go to court there where EU law allows it.

22. Changes to these terms

We may change these terms for a good reason, such as a new feature, a change in the law, or a security need. Before a change that affects you, we tell you by email and in the app, at least 30 days before it takes effect. If you do not accept it, you can end the contract free of charge before that date. If you are a business and keep using MailNail after that date, you accept the change.

If a change lets us use data from a Google or Microsoft mailbox in a new way, we ask for your consent first.

23. General

• Transfer. You may not transfer these terms without our consent. We may transfer them to a company that takes over MailNail and keeps these terms. We tell you first.
• Severability. If one part of these terms is invalid, the rest stays in force.
• No waiver. If we do not enforce a term at once, we keep the right to enforce it later.
• Whole agreement. These terms and the documents in Section 2 are the whole agreement about MailNail.
• Notices. We send notices by email to the account owner and in the app. You send notices to support@mailnail.com.
• Events outside our control. We are not liable for delays from events we could not reasonably prevent, such as an internet or provider failure.
• Language. These terms are in English. If we publish a Czech version, both have the same force.
• Businesses. If you are a business, sections 1799 and 1800 of the Civil Code do not apply to these terms.

24. Contact

Write to support@mailnail.com about anything in these terms. For privacy, write to privacy@mailnail.com. To report abuse or illegal content, write to abuse@mailnail.com.