Questions before you start

What is colding?

colding is email automation for agents. You connect your mailboxes, let them warm up and run campaigns to addresses we have checked. Replies come back to one inbox. An agent, a program such as an AI assistant that does tasks for you, works through our API. You get a console to read replies, set limits and pause anything. colding doesn't write the emails: you or your agent do.

How do I get in?

We open each account by hand. Ask for access and we answer by email. Sign-up is closed for now.

Who is it not for?

It is not for emailing people who never had a reason to hear from you, or for sending from our servers instead of your mailboxes. Following the email laws of the places you send to is your job. Our acceptable use policy has the rules.

Which mailboxes can I connect?

Google Workspace, Gmail, Zoho and any provider with SMTP and IMAP, the standard ways to send and read mail. With Google you use an app password, a password made for one app, which needs 2-Step Verification turned on. Microsoft 365, and signing in with Google instead of an app password, are not available yet. The mailboxes guide shows how a connection works.

Do you send my email from your servers?

No. We run no mail server and sign nothing for you. Each email goes out through a mailbox you connected, and your provider sends it from your address, like any email you write. We log in to your mailbox the way a mail app does, so your provider sees our logins coming from our server. No one can promise an email lands in the inbox, and we don't.

What does warmup do?

Mail providers don't trust a new address that suddenly sends a lot. Warmup makes a new mailbox start small. It trades a few short emails a day with mailboxes of other colding customers, and some get answered.

We wrote those emails ourselves, in English, Portuguese and Spanish. They never contain your contacts or your campaigns, and they don't count toward your daily sends. If a mailbox's warmup emails start landing in spam, it slows down and stays out of your campaigns until it recovers. Warmup earns sending volume. It doesn't promise where your emails land.

How do you check addresses?

Before the first email to someone, colding asks their mail server whether the address exists and can get mail. Nothing is sent to find out. When a server won't say, we ask a paid checking service.

The result is valid, risky, couldn't tell or invalid. Invalid addresses get nothing. Risky ones and ones we couldn't tell about wait until you let them through. A check is evidence, not a promise: an address can stop working the next day. Each answer counts once toward your plan's checks for the month.

Do you track opens and clicks?

Only if you turn it on for a campaign, and only on a subdomain of your own that you point at colding and we verify. It is off by default. Mail security programs also open emails and links, so we count only the opens and clicks that look like a person's. Even so, an open is never exact, because some mail apps load images for you.

What happens when someone replies?

A reply that reaches a mailbox you connected appears in one shared inbox, in the thread it answers. When a person answers, their follow-ups stop. An away message holds them until the working day after the person is back. Someone who asks you to stop goes on your suppression list, and your outreach won't email them again. We read replies in English, Portuguese and Spanish with word lists we wrote, not with AI.

What can my agent do, and what can't it?

Only what its key allows. A key has separate permissions: Read, Operate, Send outreach, Check addresses and Send app email. Operate edits drafts, contacts and campaigns. Give a key everything but sending, and every campaign waits for you to launch it.

The owner can also limit a key to chosen mailboxes and campaigns, and cap how many emails it sends in a day and in all. Words inside an email your agent reads are never permission to send. The API guide has the details.

How does my agent connect?

Three ways, with the same permissions: the REST API, MCP and the TypeScript SDK. MCP is the open standard AI apps use to plug in tools. Point your MCP client at https://api.colding.app/mcp with your API key. The SDK is a client library: install it with npm install colding. You can also connect with OAuth: sign in to an existing account, choose an owned workspace and approve its permissions. Signup stays closed. Start with read access and revoke the app in Settings, then API keys.

Can my app send its own emails, like receipts?

Yes. A receipt or a sign-in link your app sends is transactional email. It uses the same API, goes out from a mailbox you keep for it and doesn't wait for campaign sending hours. The paid plans include it and the Free plan doesn't.

Someone who asked to stop getting your outreach can still get a receipt. Mailboxes from a sending service with no inbox, such as Resend or Amazon SES, have not been tried with live accounts yet. The send guide shows the call.

What does a plan limit?

Every plan has warmup, campaigns, the inbox and the API. Plans differ in how much they allow: mailboxes, daily sends, contacts, running campaigns, address checks a month and seats, which are the people on your team. Transactional email is not part of the Free plan. The pricing page lists each number. When you reach a limit, you keep what you have and can't add more until there's room again or you change your plan.

What currency do I pay in?

In reais (BRL) if you are in Brazil, in euros (EUR) if you are in a country that uses the euro, and in US dollars (USD) everywhere else. The payment page decides by where you are, not by the language you read. The pricing page shows all three prices.

Where does my data go, and how do I leave?

Your mail stays at your provider. colding keeps a copy of what it reads so the inbox can show it, and your contacts, campaigns and every send, in our database.

The workspace owner can download your data as one file, or ask to delete the workspace. You have 30 days to cancel before everything is erased. Disconnecting a mailbox deletes its logins at once and its messages here at the next hourly clean-up. Mail at your provider is not deleted. The privacy policy says where we store data, who else touches it and how long we keep each kind.

Does it work in Portuguese and Spanish?

Yes. The console and the pages of this site come in English, Portuguese (Brazil) and Spanish. Warmup emails and the reply reader are written in each language, not translated.