Guides
Everything you can do with a mailbox that costs nothing and disappears on its own — signing up without your real address, reading mail from a test suite, and turning a domain you own into a catch-all inbox.
- 46 guides
- 10 topics
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Start here
4 guides, in the order they make sense — about 52 minutes end to end.
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Getting started
What is temp mail? Temporary email addresses, explained
The definition, the mechanics (one MX record and a mailbox that exists the moment mail arrives), temp mail against disposable, burner and alias addresses, what it is good for, the four places it is the wrong tool, and how long an address lasts.
Beginner
12 min read
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Privacy & everyday use
Sign up for anything without giving your real address
What a disposable address is, how to open one, the alias trick that keeps the service you signed up to from reading the rest of your mail, and the cases where a throwaway address is the wrong tool.
Beginner
9 min read
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Testing & CI
Test an email verification flow end to end
The full sign-up loop against a real mailbox: unique address per run, polling with a wall-clock deadline, extracting the code or the confirmation link, and working Playwright and pytest helpers.
Intermediate
22 min read
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Your own domain
Turn a domain you own into a catch-all inbox
The single DNS record, why the record itself is the proof of ownership, giving every service its own address on your domain, and the honest limits of a mailbox with no password on it.
Intermediate
9 min read
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Every guide, filed where it belongs. New ones land in these same shelves.
Getting started
What a disposable address actually is, how to open one, and what happens to the mail afterwards.
- How long a disposable inbox lasts, and what expires with it What the 5-day window applies to and what it does not, when the clock actually starts, everything that goes with a message, reading the deadline straight off the API, and the habit that stops any of it mattering. Beginner 15 min
- What is temp mail? Temporary email addresses, explained The definition, the mechanics (one MX record and a mailbox that exists the moment mail arrives), temp mail against disposable, burner and alias addresses, what it is good for, the four places it is the wrong tool, and how long an address lasts. Beginner 12 min
Testing & CI
Reading real mail from a test suite: sign-up flows, verification codes, pipelines that must not flake.
- Test an email verification flow end to end The full sign-up loop against a real mailbox: unique address per run, polling with a wall-clock deadline, extracting the code or the confirmation link, and working Playwright and pytest helpers. Intermediate 22 min
- Playwright email testing: read a code from a real inbox A fixture that opens a fresh inbox per test, a wait with a wall-clock deadline instead of a retry count, extractors anchored on your own template, three complete flows (code, magic link, password reset), and how it survives CI without a secret. Intermediate 20 min
- Cypress email testing: sign-up, OTP and reset emails A cy.task that polls a disposable inbox with a wall-clock deadline, two custom commands (fresh address, wait for mail) and two extractors, complete sign-up, one-time-code and password-reset specs, the timeouts Cypress gets wrong by default, and how it runs in CI without a secret. Intermediate 19 min
- OTP codes from email in automated tests, without flaking Where a code actually is (text, HTML, the subject line), the regex anchored on your own wording, templates that split the digits into table cells, why the newest message is not always the right one, codes that expire during a slow run, and extractors for jq, Python and TypeScript. Intermediate 14 min
- GitHub Actions: an end-to-end job that reads real email Complete workflows for Playwright and pytest, why there is no secret to store, the one HTTPS egress rule (and what to allow on a hardened runner), shards and retries without shared mailboxes, the four timeouts that have to nest, reading a failure from the artifact, and the optional cleanup step. Intermediate 15 min
API & automation
Scripts, schedulers and everything else you can drive over three HTTP endpoints.
- Disposable email API: automate an inbox from a script The three calls in full, paging past the first fifty messages, the two separate rate budgets, deleting what you are done with, and the error slugs worth branching on. Intermediate 22 min
- Python: receive email with a disposable inbox API, no key A drop-in module on requests (fresh address, wait with a deadline, read, delete, download), the asyncio version on httpx that waits on five inboxes at once, pagination with the before cursor, attachments to disk, 429 handling, a pytest fixture, and a table of the ways this goes wrong in production. Intermediate 23 min
- Node.js temp mail API: read an inbox with fetch, no key A drop-in TypeScript module on the built-in fetch (fresh address, wait with a deadline, read, delete, download), the same in plain JavaScript, what changes on Deno and Bun, pagination with the before cursor, streaming an attachment to disk, 429 handling, a Vitest test, and a table of the ways this goes wrong in production. Intermediate 19 min
- Waiting for an email in code: polling without a webhook What push and pull each cost you and why a receive-only service has neither webhook nor callback, the four-line loop everybody writes first and the five things wrong with it, why a deadline is the only stopping condition that survives a slow queue, how to choose an interval when the floor is one request a second, reading Retry-After instead of guessing, the whole table of refusals so a 404 is never mistaken for an empty mailbox, deciding which message is yours before you open it, acting exactly once when a poll is retried, and the server-side wait an agent can use instead of a loop. Intermediate 29 min
Privacy & everyday use
Signing up without handing over your real address — and being honest about where that stops working.
- Sign up for anything without giving your real address What a disposable address is, how to open one, the alias trick that keeps the service you signed up to from reading the rest of your mail, and the cases where a throwaway address is the wrong tool. Beginner 9 min
- Email attachments on a disposable address: limits and safety What counts as an attachment, where the 5 MB ceiling really falls once base64 has had its way, downloading from the inbox and from the API, and why every file comes back as an anonymous binary. Beginner 11 min
- Email tracking pixels: what the sender learns when you open How a tracking pixel actually works, what a single request tells the sender, why remote images are blocked here by policy rather than by editing the message, and the louder signal that blocking them leaves untouched. Beginner 10 min
- Why sign-up forms block disposable email, and what to do How disposable-domain blocklists are built and kept, the three checks a form can run (list, MX, catch-all probe, provider score), what blocking costs the sites that do it, why the local part is irrelevant, the three honest ways round a refusal — your own domain, a domain kept off the lists, or an alias — and how to block well if you run the form. Beginner 10 min
- Burner email, alias or temp mail: which one, for what The three tools defined by who ends up reading the mail, a side-by-side across privacy, lifetime, recovery, blocklists and cost, the decision rule (would you mind losing the account?), how to use them together, the alias services worth knowing, and the three situations where none of them is the answer. Beginner 9 min
- Plus addressing: what you+tag@ hides, and what it doesn’t What subaddressing is and where it is written down, a provider-by-provider table of who accepts a plus tag and what else they accept, the three jobs it does well, the four it cannot do, why sign-up forms reject the character, and a side-by-side of the alternatives that change the address instead of decorating it. Beginner 13 min
- How to stop spam email: what works, and what makes it worse Where the spam actually came from and how to tell the four sources apart, why the link in the message and the button beside the sender are two different requests made by two different people, what your provider learns from spam, block and delete, the three header lines that settle whether an unsubscribe is safe, and the address-per-service ladder that is the only durable fix. Beginner 17 min
Your own domain
One MX record, a catch-all inbox, and an address per service that you can burn one at a time.
- Turn a domain you own into a catch-all inbox The single DNS record, why the record itself is the proof of ownership, giving every service its own address on your domain, and the honest limits of a mailbox with no password on it. Intermediate 9 min
- Unlimited test accounts on one catch-all domain Why a catch-all domain is the right shape for QA, the one DNS record, a naming scheme that makes a mailbox say which pipeline made it, reading any address over the same three calls, keeping a test domain off the blocklists, sharing one domain across a team, and the limits that apply. Intermediate 11 min
AI agents & MCP
Letting an agent open an inbox, wait for the confirmation code and carry on without you.
- MCP email inbox: let an AI agent confirm its own sign-up Connecting an MCP client in one line, the four tool calls that carry an agent through a sign-up, why wait_for_message returns before the mail does, and what to write in the agent’s own instructions. Intermediate 13 min
- Email inbox for Claude Code, Cursor and Windsurf via MCP The configuration for seven clients (Claude Code, Claude Desktop, Cursor, Windsurf, VS Code, Codex CLI, Gemini CLI), how to check the server answers from a shell, the six tools, the sign-up loop in four calls, what to write in CLAUDE.md or the rules file, and a troubleshooting table. Beginner 14 min
- Email for AI agents: sign-up verification without a human Why the email step breaks agents, the two ways to give one an inbox (MCP with a blocking wait, or a REST tool), the tool functions in Python for LangChain and the OpenAI Agents SDK and in TypeScript for the Vercel AI SDK, the four-call loop, the alias rule, guardrails for an unattended agent, and notes for browser agents. Intermediate 21 min
Email & deliverability
MX, SPF, DKIM, DMARC, bounces, and why a message that was sent never arrived.
- Email headers: how to read one, and what it proves What the header block is and how it differs from the SMTP envelope, where to open the raw source in the mail app you already use, how to read the Received chain from the bottom up, the four fields that all claim to be the sender, what a pass or a fail in Authentication-Results really means, the five things a header can never tell you, and what is left to check when the message landed at a disposable address. Beginner 21 min
- SPF and DMARC for a receive-only domain: stop spoofing Why a domain that never sends can go straight to the strictest SPF and DMARC on day one, the three records in full, the DKIM one you publish empty, checking your work with dig, and the parked-domain advice that would silently break your inbox. Intermediate 19 min
- Email bounces: how to read one, and what each code means What a bounce actually is and the two very different moments it happens, the three parts of a delivery report and which line carries the reason, how to read a reply code and an enhanced status code, the dozen codes that account for almost every bounce anybody reads, what can and cannot bounce at a disposable address, the bounces that belong to the hour you point your own domain here, and why a report sometimes arrives for a message you never sent. Beginner 22 min
- MX records explained: priority, lookups and what breaks What an MX record is and the four things it is not, reading one with dig, nslookup or host, what the preference number actually decides and why a backup host is not a second chance, the seven steps a sending server takes, what happens when there is no MX at all and what a null MX says instead, the six ways the record breaks, the single record that points a domain here, and why an hour is not long enough. Beginner 18 min
- Email address validation: what a regex can and cannot prove The four questions hiding inside « is this a valid email address », why there is no official regex and which one to use instead, the six legal addresses forms wrongly throw out, the three length limits worth hard-coding, the one DNS lookup that catches the commonest real mistake, why an SMTP probe answers yes to addresses that do not exist, the honest case for and against blocking disposable domains, and the confirmation loop that is the only check that proves anything. Intermediate 21 min
Troubleshooting
When mail does not turn up, the API answers 404, or a form refuses the address outright.
Comparisons
Named services, dated facts, and the places where this one loses.
Alternatives
GrabMail against one named service at a time: what each does well, what each costs, and which to pick for which job.
- Temp Mail (temp-mail.org) alternative: GrabMail vs Temp Mail Temp Mail deletes mail after one to two hours, assigns your address and sells choosing one for $10 a month; GrabMail keeps mail five days, lets you type any address and reads it over a keyless API. The prices and limits as published, and when the bigger site is the better choice. Beginner 10 min
- 10 Minute Mail alternative: GrabMail vs 10minutemail 10 Minute Mail assigns a private address and deletes it after ten minutes; GrabMail lets you type any address, keeps mail five days and adds a keyless API, your own domain and an MCP server. When a ten-minute inbox is right, and when it is not. Beginner 9 min
- Guerrilla Mail alternative: GrabMail vs Guerrilla Mail Both are free, keyless and let you pick your address. Guerrilla Mail keeps mail one hour, runs ads and sells a custom domain for $9.99 a year; GrabMail keeps mail five days, runs no ads, adds an MCP server, and takes your domain for free. Where each one fits. Beginner 9 min
- Mailinator alternative: GrabMail vs Mailinator Both run public inboxes anyone can read. GrabMail adds a free keyless API, your own domain at no cost and a free MCP server; Mailinator sells private domains, webhooks, SMS testing and SDKs from $99 a month, with a capped free Verified Pro tier. Beginner 11 min
- YOPmail alternative: GrabMail vs YOPmail Both let you name any inbox and point your own domain at them for free. YOPmail keeps mail eight days, has 225+ alternate domains and ads, and no API; GrabMail keeps mail five days, has far fewer domains and no ads, and adds a keyless API and an MCP server. Where each fits. Beginner 8 min
- mail.tm alternative: GrabMail vs mail.tm Both are free with no paid tier and no API key. mail.tm gives each mailbox a password and a token, keeps mail seven days and pushes events; GrabMail needs no token at all, keeps mail five days, and adds your own domain, attachments and an MCP server. Where each fits a script or an agent. Beginner 10 min
- EmailOnDeck alternative: GrabMail vs EmailOnDeck EmailOnDeck gives a private random address for about a day, and a crypto-paid Pro tier with sending, chosen addresses and an API; GrabMail gives any address, five days, a keyless API and your own domain for free, in public mailboxes. Where each one fits. Beginner 9 min
- Maildrop alternative: GrabMail vs Maildrop Both are free, keyless and public, and both let you make up any address. Maildrop strips attachments, keeps ten messages and wipes after 24 idle hours; GrabMail keeps five days and 5 MB attachments, and adds your own domain and an MCP server. Where each one fits a script. Beginner 9 min
- TrashMail alternative: GrabMail vs TrashMail (Aionda Mail) TrashMail (now Aionda Mail) forwards disposable addresses to your real inbox, with per-address expiry and forward counts, 25 addresses free and 10,000 on Plus at 1.99 € a month; GrabMail keeps mail in a public inbox you read on the web or over a keyless API. Which one for which sign-up. Beginner 10 min
- temp-mail.io alternative: GrabMail vs temp-mail.io temp-mail.io keeps free mail one day, runs ads and sells the API, custom domains and its MCP server as Premium; GrabMail keeps mail five days, runs no ads, and gives the API, your own domain and an MCP server away. The published limits, and which fits which use. Beginner 10 min
- MailSlurp alternative: GrabMail vs MailSlurp MailSlurp sells a full testing platform from $49.99 a month with a capped free plan; GrabMail gives a keyless API, your own domain and an MCP server away for nothing. Where each one fits, with the prices and limits as published. Beginner 11 min
- Mailosaur alternative: GrabMail vs Mailosaur Mailosaur has no free plan and starts at $20 a month billed annually; GrabMail is free with no account. What each one is for, the limits as published, and when the paid QA platform is worth it. Beginner 10 min
- Mailsac alternative: GrabMail vs Mailsac Both offer make-up-any-address public inboxes. Mailsac counts API calls against a monthly quota (1,500 free) and sells private addresses, custom domains, webhooks and websockets from $18 a month; GrabMail’s API is keyless with no quota, and your own domain is free. Beginner 10 min
- testmail.app alternative: GrabMail vs testmail.app testmail.app gives unlimited tagged addresses on an assigned namespace, 100 emails a month free and paid plans from $9; GrabMail gives any address, a free domain of your own and a keyless API with no monthly cap. The limits as published, and which fits which suite. Beginner 10 min
- Mailtrap alternative: GrabMail vs Mailtrap Mailtrap captures outbound mail in a sandbox and sells sending; GrabMail receives inbound mail at real addresses with a keyless API. Which one your test needs, what the free Sandbox plan caps, and the one case where they overlap: Mailtrap’s Agent Inbox. Beginner 10 min
- Mailpit alternative: GrabMail vs Mailpit and MailHog Mailpit (and the unmaintained MailHog) capture your application’s outbound SMTP on your own machine; GrabMail receives real inbound mail at hosted addresses with a keyless API. What each is for, Mailpit’s defaults, and the tests that need both. Beginner 9 min
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