CosmoSia vs black.com
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CosmoSia
Create a personalized email address with your own domain, offering carrier-like ease of use and robust privacy features. Manage multiple email accounts, block unwanted messages, and enjoy a user-friendly interface. Ideal for those seeking a professional or custom email solution.
- Create custom email addresses
- Manage multiple email accounts
- Block unwanted emails
- Easy setup
- Carrier-like usability
- Privacy-focused
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Recommended for those who are considering moving away from carrier email. You can create "XX@cosmosia.email" which is as easy to use as your carrier email! Made in Japan, so you can be sure of your privacy. Make your email more fun! The long-awaited iOS version of the free email app with over 1 million users is now available! - Just tap! The all-new "Reactions" feature Get your feelings across without words: Just like in a chat, react to emails with emoji. Reaches the other person even without the app: When you add a reaction, the recipient automatically receives a clear notification email. No matter which email service they use — Gmail, docomo mail, Yahoo! Mail, and more — your "I saw it" comes through loud and clear. Stay connected like a conversation: Even in group exchanges, you can see at a glance who reacted and how, so conversations keep flowing and stay fun. - You can create your own email address! You can create your own e-mail address such as XX@cosmosia.email. You can use email addresses such as XX@cosmosia.email. The email address will be linked to your phone number like a carrier email address, so please consider this when you are thinking of moving from a carrier email address! Email address is available only when you purchase the subscription "CosmoSia Email Plan (Monthly)". We also recommend this service when you move to ahamo, povo, LINEMO, or other plans that do not include carrier email! ==================== - You can manage multiple email services at once. IMAP4 (Gmail, docomo mail, etc.) is supported. - It is a standard email application for low-cost smartphones and MVNOs. It's easy to use, just like a carrier email, and it's popular among low-cost smartphone users! - Easy to set up Just set your email address and password and you're ready to go. Organize your mailbox now. - No more unwanted e-mails! We support a "reject list" function that allows you to prevent unwanted e-mails from entering your inbox. - Basic functions are free! The installation is free and the basic functions are free no matter how many times you use them. A predetermined usage fee is required to use CosmoSia Mail. You will have to pay for the communication charges incurred when sending and receiving emails. ==================== The following email services can be used docomo mail au-mail R mail Y! mobile mail Yahoo! JAPAN mail iCloud mail Gmail Outlook/Hotmail mineo mail so-net mail BIGLOBE mail We support the setup of many other email services. * You cannot use your UQ mobile email address (XX@uqmobile.jp). Please look forward to future updates for support of other mail services! ==================== About the trademark docomo mail is a trademark of NTT DOCOMO, INC. in Japan.
black.com
Secure and encrypted email with a personalized @black.com address. Features AI writing tools for effortless composition, unlimited storage, and alias addresses to manage spam. Protects your data with zero-access encryption and app-based two-factor authentication.
- Personalized @black.com email address
- Zero-access encryption
- AI-powered email composition
- Unlimited storage (25GB + annual increase)
- Spam-free alias addresses
- App-based two-factor authentication
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@black.com email address An email address is a reflection of your personal brand. Stand out with your own @black.com address that low-budget alternatives simply can't match. Secure & encrypted email Zero-Access Encryption secures your data with a key derived from your password. This means that not even we can access the contents of your stored emails. Our app-based two-factor authentication protects your account even if your password is compromised. Write emails effortlessly Supercharge your email experience with our integrated AI tools. Let the AI create, correct, optimize, and translate your messages. Unlock a whole new level of productivity and compose polished emails in a few seconds! Completely optional, of course. Unlimited* storage You start with 25 GB and get 2 GB of additional storage every year - forever. With normal usage, you will never run out of space. Alias addresses for a spam-free inbox Memorable and removable alias addresses like redcat42@black.com that you can use for newsletters etc. keep your inbox spam-free - forever. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula
Screenshots
Verdict
The clearest difference is review sentiment: black.com at 67% against CosmoSia's 18%. black.com also leads on rating (3.6 vs 1.0) and ads (none vs shown). On price, update cadence, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. CosmoSia sells 1 in-app purchase, starting at $2.99 per month and black.com sells 1 in-app purchase, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.
black.com holds the better App Store score, 3.6 against 1.0. That said, the two scores are not equally well evidenced: black.com has 9 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 18% of CosmoSia's written reviews are positive against 67% of black.com's.
CosmoSia ships an update every 3 weeks, black.com every 6 weeks. The most recent releases landed on September 21, 2026 and September 17, 2026 respectively.
| Parameter | CosmoSia | black.com |
|---|---|---|
| Price | Free | Free |
| Rating | 1.0 (1 ratings) | 3.6 (9 ratings) — better |
| Positive reviews | 17.9% of reviews | 66.7% of reviews — better |
| Number of ratings | 1 | 9 — better |
| Update frequency | Every 3 weeks — better | Every 6 weeks |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 16.0 — better | 16.4 |
| Further details — not scored | ||
| Size | 219 MB | 14 MB |
| Age rating | 4+ | 4+ |
| Developer | ACCESS CO., LTD. | black.com GmbH |
Customer experience
CosmoSia
black.com
In-app purchases
CosmoSia
- CosmoSia Mail Plan(Monthly)7 Days trial$2.991 Month
black.com
- Membership$4.991 Month









