These are three of the oldest free inbox sites. None needs an account for basic use. You type a name, or the site picks one, and mail starts to arrive. They differ in how long mail stays, who can read it and what you can do with an address.
This guide takes each service in turn. Every fact comes from the service's own site, read in October 2026. We used no inbox and sent no mail. BillionVerify is an email verification service, and we do not run temporary inboxes. For the basics, read what temp mail is. For a wider table of services, use our 10 minute mail alternatives guide.
Key facts (checked October 2026):
- YOPmail's alias page says nobody needs a password to open one of its inboxes, and the site keeps messages for 8 days.
- Guerrilla Mail's about page warns that anybody holding an Inbox ID can read that inbox, and says incoming mail is kept for 1 hour.
- Mailinator's FAQ says public mail sent to @mailinator.com lasts a few hours, and that any visitor may read it.
- Mailinator is receive-only, per its FAQ, while YOPmail allows sending only between YOPmail addresses.
- BillionVerify's open collection of throwaway domains held 220,601 entries on October 27, 2026, and yopmail.com, guerrillamail.com and mailinator.com are all in it.
What Makes an Inbox Public?
A public inbox has no owner. There is no account, so there is no password to check. Whoever types the same name sees the same mail.
Each service says so in its own words:
- YOPmail: "inboxes are public and password free."
- Guerrilla Mail: "anyone who knows your Inbox ID may access your inbox."
- Mailinator: "All emails are public."
A name works like a shared door code. A long random one is hard to guess. A short common one is not. That is why such a box suits a one-off confirmation and not an account you plan to keep.
How YOPmail Works
The YOPmail Login Box
YOPmail asks for a name on its home page. The box is labelled Login, but a name is all it wants. There is no sign-up step and no YOPmail login in the usual sense. Mail sent to that name lands in a box that anyone can open.
Rules and Retention
The site lists its rules under a short note called Additional:
- Every inbox already exists, and none is ever deleted.
- Messages stay eight days, and you can remove them sooner.
- Replies are possible.
- Sending anonymous mail is prohibited. One YOPmail address may write to another.
It also sorts disposable services into three groups: a temporary inbox for a limited time, automatic forwarding to a personal address, and aliases. YOPmail puts itself in the first group, with the difference that its boxes do not expire.
Screenshot: the retention and sending notes on the YOPmail home page.
The Alias Feature
Every box is public, so YOPmail gives each one a unique alias. The alias shows at the top of the real inbox. Mail sent to it is forwarded to the original. Anyone who opens the alias as a name finds an empty box.
YOPmail also advises picking difficult names. It admits that some people choose simple ones for convenience.
Screenshot: the YOPmail alias page and its diagram of the forwarding path.
How Guerrilla Mail Works
Guerrilla Mail hands out a random address as soon as you open the site. The about page says you may choose your own instead. The main screen has a menu of 11 domains, a message list and a Scramble Address checkbox. Tabs along the top read Email, Compose, Tools and About.
The ID and the Scrambled Address
There is no registration, so the ID is the only key. The FAQ says a random one is best.
A scrambled name is a second name for the same box. The FAQ explains that it can be known only when the ID is known, and that it cannot serve as an ID itself. A harder ID gives better protection.
One Hour of Storage
According to the FAQ, the current version keeps all incoming email for 1 hour, and every address works all the time. New mail first waits in quarantine. When someone checks the box, the mail moves in and gets one more hour, or until it is deleted. Mail that nobody collects within an hour is removed.
The privacy section adds that logs are normally off, because the server lacks the resources to keep them. It also says the site uses third-party cookies, including Google Analytics and Google AdSense.
You can use a domain you own for $9.99 USD per year, paid by Bitcoin or PayPal, per the main screen. The mail server, Go-Guerrilla, is an open source project, and an API is available.
Screenshot: the privacy and technology sections of the Guerrilla Mail about page.
How Mailinator Works
Mailinator calls itself more than a temporary address service. Its site describes workflow testing by email and SMS for dev and QA teams. A free public part is still there. Most people mean that part when they use the name.
The Mailinator Public Inbox
Every possible @mailinator.com address already exists. Any Mailinator email address is therefore ready before you use it. You make up a name, give the address to a site, then type the name into the public field. That opens a Mailinator inbox with no login.
The FAQ lists the limits of a Mailinator public inbox:
- Mail is deleted for good after a few hours.
- Anyone can read a Mailinator email, so do not expect privacy.
- The system is receive-only and cannot send.
- Attachments are not allowed.
- Size, rate and spam limits apply.
Mailinator also says it keeps no logs of website access and stores no identifying details, such as an IP address, for the public site.
Private Domains for Testing
Paid plans swap the shared name space for a private domain. Mailinator's temporary email page gives @yourcompany.testinator.com as an example. Each Mailinator inbox there stays behind a team password, with a REST API and webhooks.
The pricing section lists Verified Pro at $0 with verification, Business at $79 a month and Business Plus at $159 a month. Enterprise has custom pricing. A Mailinator email on a private domain is a different product from the Mailinator public inbox.
Screenshot: Mailinator's table comparing public inboxes with private domains.
YOPmail vs Mailinator vs Guerrilla Mail
The table sets the three services next to each other, using the rules above.
| Question | YOPmail | Guerrilla Mail | Mailinator |
|---|---|---|---|
| Who can read it? | Whoever types the name | Whoever holds the ID | Anyone, for public names |
| Account needed? | No account or password | None | None for public names |
| How long does mail stay? | 8 days | 1 hour | A few hours |
| Can it send? | Replies, plus mail to other YOPmail names | A Compose tab | It only receives |
| Own domain | A page to add one | $9.99 USD a year | Private domains on paid plans |
| Aimed at | People avoiding spam on sign-ups | People keeping a real inbox clean | Test teams |
Alternatives for Each Service
The three are public by design. When one does not fit, the gap is usually time, privacy or testing. Our comparison guide covers more services, and the points below draw on it.
Guerrilla Mail Alternatives for Longer Storage
One hour is short. YOPmail keeps mail for days, though any visitor can read it. Mail.tm holds messages for 7 days and guards the mailbox with a generated password, according to its site.
Mailinator Alternatives for Private Inboxes
Mailinator's own answer is a paid private domain. Maildrop and Mail.tm publish APIs, and Mail.tm adds a password.
YOPmail Alternatives With a Timer
10MinuteMail deletes the address and its mail after ten minutes, and it says only you can see the box. YOPmail does the opposite, since its inbox names never expire.
What Happened to TrashMail?
German readers often look for TrashMail. On October 27, trashmail.com answered with a redirect to mail.aionda.com. That site presents itself as encrypted groupware from Germany, not as a disposable inbox. For that reason this guide does not compare it.
When a Public Inbox Is a Poor Fit
- You want the account later. A password reset goes to the same open box. There is no YOPmail login that could recover it, and a Guerrilla Mail reset can arrive after an hour has passed.
- The message is private. None of the three can promise that nobody else reads it.
- You need to send. A Mailinator inbox cannot send, and YOPmail writes only to its own addresses.
- The site refuses the address. Many sites check the domain against a blocklist, and these domains are on public lists. A refusal means the site wants a mailbox you own.
How Websites Handle These Domains
A site that wants real contact details reads the part after the @ sign. It looks that domain up in a blocklist of disposable providers. Public lists of this kind include the main domain of each service here.
BillionVerify keeps its list in the open. The disposable library on GitHub says its entries are merged from nine community lists and updated hourly. A search of the data file found all three primary domains. The README's own example checks a mailinator.com address.
The free temp mail checker on our site runs the same domain check on one address. To see why sites block these names, and how the signals add up, read how sites detect temporary email.
Some teams also verify the address after a form is sent. A BillionVerify account gives 20 credits on each day you use it, up to 600 a month, and they never expire. Servers sit in France (EU), and a data processing agreement can be signed. An unknown result costs nothing.
The result labels in BillionVerify's checker: fake, throwaway, role account and deliverable.
Two related tools cover other signup fields. The reverse email lookup shows what sits behind a sender's address. When a form also asks for a phone number, the phone number checker shows whether it is valid and what kind of line it is.
FAQs
What is YOPmail?
YOPmail is a free disposable inbox service at yopmail.com. It needs no registration, and every name already has a box. Mail stays for eight days, and any visitor can open it.
Is there a YOPmail login or sign in?
YOPmail has no account system for basic boxes, so there is no YOPmail login to remember. The Login field takes a name and nothing else. To open a box, enter the name you used.
What is Mailinator?
Mailinator is a testing platform for email and text messages, with a free tier open to everyone. That tier gives every Mailinator email name a live box. Public messages are removed within hours.
YOPmail vs Mailinator: Which Keeps Mail Longer?
YOPmail holds mail the longer of the two. Messages stay for 8 days and can be answered. A Mailinator inbox on the public side holds mail for a few hours and only receives.
What Are Good Guerrilla Mail Alternatives?
The right Guerrilla Mail alternatives depend on the job. YOPmail suits mail you want to check for days. A paid Mailinator plan suits team testing. Neither makes a public box private.
Can Anyone Read a Guerrilla Mail Inbox?
Whoever knows the ID can open the matching box, according to the site. A random ID is difficult to guess. The scrambled alias protects the alias, not the ID.
Do Websites Block These Three Services?
Some sites do, because public lists of disposable domains include all three. Each site decides for itself. A rejected address is a cue to use a mailbox you own.
Does BillionVerify Offer a Temporary Inbox?
No. BillionVerify does not provide temporary inboxes. It offers a free disposable email check and an open domain list, so site owners can see which addresses come from these services.