# Mailfully > Mailfully is a transactional email API for developers. Your app sends receipts, password resets and sign-in links with one API call, and can receive email by webhook. 5,000 emails a month are free, and paid plans start at $19. ## Pages - [Home](https://mailfully.com/): What Mailfully is, what it costs, and how sending and receiving work. - [Pricing](https://mailfully.com/pricing): Every plan's price, allowance and overage rate, a cost calculator against other providers, and the Enterprise option. - [Inbound email](https://mailfully.com/inbound-email): Receive email at your own domain or a hosted address. Each message arrives by webhook, and the API returns its body. - [AI agents](https://mailfully.com/ai-agents): Give an AI agent its own API key and a hosted address for replies, then try it in test mode. - [Email API alternatives](https://mailfully.com/alternatives): How Mailfully compares with other email APIs on price and features, with a page for each provider. - [About](https://mailfully.com/about): Who runs Mailfully and how to reach the team. - [Security](https://mailfully.com/security): How Mailfully protects data and API keys, and how to report a security problem. - [Contact](https://mailfully.com/contact): A form that reaches the team for sales, Enterprise pricing and support. - [Privacy Policy](https://mailfully.com/privacy): What data Mailfully handles, the subprocessor register, retention by plan, and your rights. - [Terms of Service](https://mailfully.com/terms): Accounts, acceptable use, fees and overage, suspension and appeals, and liability. - [The Outbox (blog)](https://mailfully.com/blog): Notes from the Mailfully team on deliverability, transactional email APIs, and the unglamorous plumbing that keeps mail out of the spam folder. - [Resend alternative that stays cheap at scale](https://mailfully.com/alternatives/resend): A Resend alternative for teams watching the bill grow: 5,000 emails a month free, $0.40 per 1,000 overage against $0.90, and a dedicated IP on any paid plan. - [Postmark alternative with a real free plan](https://mailfully.com/alternatives/postmark): A Postmark alternative at a third of the price: 50,000 emails for $19 against $55, $0.40 per 1,000 overage against $1.80, and 5,000 a month free against 100. - [SendGrid alternative with a free plan that lasts](https://mailfully.com/alternatives/sendgrid): A SendGrid alternative whose free tier does not expire: 5,000 emails a month free, at least 30 days of logs, and a dedicated IP for $29 instead of $89.95. - [Brevo alternative for transactional email](https://mailfully.com/alternatives/brevo): A Brevo alternative for transactional email: no forced unsubscribe header, no contact ceiling tied to volume, and 50,000 emails for $19 against $56. - [Mailgun alternative with simpler pricing](https://mailfully.com/alternatives/mailgun): A Mailgun alternative with simpler pricing: 50,000 emails a month for $19 against $35, and a free plan of 5,000 a month against 100 a day. - [Mandrill alternative with no Mailchimp plan](https://mailfully.com/alternatives/mailchimp-transactional): A Mailchimp Transactional alternative with no plan to buy: 50,000 emails a month for $19 against $60, and a free plan of 5,000 a month. ## Blog posts - [How to set up SPF, DKIM, and DMARC for your sending domain](https://mailfully.com/blog/spf-dkim-dmarc-setup): Set up SPF, DKIM, and DMARC for your sending domain, check a real message, and fix common DNS and alignment mistakes. - [Getting Outbound Email to Work on DigitalOcean](https://mailfully.com/blog/digitalocean-blocks-smtp-ports-ses-2587): Our Ghost install on a DigitalOcean droplet couldn't send its own invites, and weeks with support went nowhere. Some providers also answer on a high port like 2587, and one number in the config gets a droplet sending again. - [Send your transactional mail from a subdomain](https://mailfully.com/blog/send-transactional-mail-from-a-subdomain): SPF doesn't cascade to subdomains, and every name carries exactly one record. Put those together and sending from your root domain leaves you one DNS edit away from breaking every email your company sends. ## Documentation - [Introduction](https://mailfully.com/docs/introduction): What Mailfully is: an API for sending and receiving transactional email, with delivery tracking, webhooks and a Node SDK. - [Quickstart](https://mailfully.com/docs/quickstart): Send your first email through the API, from creating a key to delivery. - [API reference overview](https://mailfully.com/docs/api-reference/overview): Base URL, authentication, error format, rate limits and pagination for the API. - [Verify a domain](https://mailfully.com/docs/guides/verify-a-domain): Add a sending domain, publish its DNS records, and verify it before sending live email. - [Test mode](https://mailfully.com/docs/guides/test-mode): Send with a test key to try the real send path without delivering mail, and force bounces and complaints per recipient. - [Webhooks](https://mailfully.com/docs/guides/webhooks): Delivery, bounce, complaint and received-mail events pushed to your endpoint as signed HTTP callbacks. - [Receiving email](https://mailfully.com/docs/guides/receiving-email): Receive mail at a verified domain or a hosted mailfully.app address, get a webhook, and read the body, attachments and raw message. - [API key security](https://mailfully.com/docs/concepts/api-key-security): Choose the narrowest scope, keep test and live keys apart, store secrets outside your repository, and rotate on a schedule. - [Quotas and plan limits](https://mailfully.com/docs/concepts/quotas-and-plan-limits): What each plan includes before a limit applies: sent and received volume, overage ceiling, retention window and spend cap, plus how the sending-domain cap works. - [IP pools](https://mailfully.com/docs/concepts/ip-pools): Which IPs your mail leaves from, how an account moves from the warm-up pool to the shared pool, and when a dedicated IP is worth buying. - [Node.js SDK](https://mailfully.com/docs/sdks/node): Install the mailfully package, create the client, handle the { data, error } result, and see which endpoint each method calls. - [CLI](https://mailfully.com/docs/sdks/cli): Install the mailfully CLI, authenticate once, then send mail, verify domains, and read the message log and analytics from a terminal. - [Suppressions](https://mailfully.com/docs/guides/suppressions): How addresses land on your suppression list, what happens when you send to them, and how to list, add and remove entries. - [A leaked API key](https://mailfully.com/docs/troubleshooting/leaked-api-key): Contain an exposed key: when to rotate or revoke it, how the grace window on a rotated key works, and how to audit what it could reach. - [Retrieve a received email](https://mailfully.com/docs/api-reference/receiving/get): Retrieve one received email with its body, headers, receipt verdicts, attachment metadata and a download link for the original message. - [List received email attachments](https://mailfully.com/docs/api-reference/receiving/list-attachments): List the attachments of one received email, each with a download link that saves under the attachment's own filename. - [Full documentation sitemap](https://mailfully.com/docs/sitemap.xml): Every documentation page. ## Developers - [Node.js SDK and CLI (mailfully)](https://www.npmjs.com/package/mailfully): Official Node.js client and CLI. ## Account - [Sign up](https://dashboard.mailfully.com/register): Create a free account. - [Sign in](https://dashboard.mailfully.com/signin): Open the dashboard. - [Contact](https://mailfully.com/contact): Talk to sales or support.