How to use SimpleX Chat: the messaging app without a phone number or central servers

Privacy and security in personal communications These are increasingly in-demand aspects within the digital world. That's why proposals such as SimpleX Chat are becoming increasingly popular, especially among users who want to protect their information and ensure that their conversations are not subject to spying or unauthorized data collection.

In addition to security, SimpleX Chat reinvents the concept of private messagingIts internal workings, its differences from other similar apps, and its ease of use make it an attractive option for those looking to keep their conversations away from prying eyes.

What is SimpleX Chat and how is it different from other messaging apps?

SimpleX Chat is A private and secure messaging platform, designed from the ground up to maximize user privacyUnlike WhatsApp, Signal, or Telegram, SimpleX doesn't use any traditional user identifiers, such as phone numbers or email addresses. This means that no personal data is required to start using the application. and therefore is not stored or shared on the servers.

SimpleX Chat's architecture breaks with the centralized framework of most applications. It uses its own open protocol, Simple Message Protocol (SMP), which transmits messages through intermediate servers, but at no time stores information that would permanently identify users. Privacy is absolute, as neither senders nor recipients leave a lasting trace..

At a technical level, Conversations are established using single-use links or QR codes, and messages are stored only on users' devices, in an encrypted and portable database. So, if you ever want to switch devices, you can transfer your chats easily and securely.

Main features of SimpleX Chat

 features that distinguish it from other alternatives on the marketThese are some of the most relevant ones:

• End-to-end encryption (E2E): All messages are protected so that only the sender and recipient can read them.
• Free and open source software: The code is available for review and improvement, enhancing transparency and trust.
• Self-destructing messages: You can set your messages to disappear after a certain amount of time.
• No need to provide a phone number or email: Registration is completely anonymous.
• Clear and responsible privacy policy: SimpleX minimizes data processing to what is strictly necessary.
• Possibility to choose servers and even self-hosting: You can use SimpleX's public servers or create your own private environment.
• 2FA (two-step authentication): Increase the security of your chats.

Additionally, SimpleX uses temporary identifiers for message queue pairs., independent for each connection between users. This means that each chat has its own ephemeral identity, preventing long-term correlations or tracking.

Internal operation and SMP protocol

The core of SimpleX is the Simple Message Protocol (SMP), developed as an alternative to the traditional use of servers and single communication channels. SMP is based on the transmission of messages through unidirectional queues that only the recipient can unlock. Each message is individually encrypted and temporarily stored on servers until it is received and permanently deleted.

The protocol runs on TLS (Transport Layer Security), providing integrity in communications and guaranteeing server authenticity, complete confidentiality and protection against interception attacks. The fact that each user can choose which server to use or even self-hosting your own relay guarantees an extra level of decentralization and control over the data.

Another fundamental difference compared to other systems is that The initial public key exchange always occurs out of band, meaning it's not transmitted over the same channel as the messages, making man-in-the-middle (MitM) attacks more difficult. This drastically reduces the risk of someone being able to intercept and decrypt your messages without your knowledge.

Advanced privacy and MitM attack protection

One of the strengths of SimpleX Chat is its focus on mitigate the well-known man-in-the-middle or MitM attacksIn many messaging services, an attacker can intercept the public key during the key exchange, impersonate it with their own, and thus read messages without the recipients' knowledge.

SimpleX solves this problem moving the initial public key exchange to an external channel, for example, via a QR code or a link sent by another means. The attacker can't predict which channel will be used, and therefore, the probability of intercepting the key is much lower. However, it is always advisable for both parties to verify the integrity of the key they exchange., just as recommended for other encrypted apps.

For users concerned about advanced spying, This architecture provides an additional layer of protection that is difficult to match with most conventional solutions..

Differential advantages of SimpleX compared to XMPP, Signal and other apps

Comparing SimpleX with other secure platforms like XMPP (using OMEMO) or Signal, key differences can be seen:

• Metadata protection: SimpleX doesn't associate your chats with any identifier, not even a permanent nickname. You can appear in groups with an incognito nickname.
• Creating and managing groups: Groups in SimpleX are already encrypted by default, although it's recommended that groups be small and managed by trusted contacts. Access can be controlled via single-use invites or QR codes.
• Absolute decentralization: You don't depend on a central server; you can choose public or private servers.
• Transparency and code auditing: Being open source, the community can quickly detect and correct any security flaws.

While with XMPP you have to configure encryption manually in certain cases and depend on the reliability of the server, in SimpleX the entire process is automatic and the message history is never centralized or exposed.

Getting Started: How to Install and Configure SimpleX Chat

The process to get started with SimpleX is very simple and straightforward, suitable for any type of user, from novices to experienced digital privacy users.

1. Download the app: SimpleX is available for free on the Apple App Store, the Google Play Store, and F-Droid (for Android users who prefer open source software). Install the app on your usual device.
2. First boot and profile creation: When you open the app, no registration is required. You simply receive a temporary ID that you can share with anyone using a one-time link or QR code.
3. Advanced configuration: You can customize the look and feel or manually select the SMP server that best suits you, or even opt for your own if you want complete control over your data.
4. Import or export messages: Thanks to the encrypted and portable database, you can transfer your chats to another device at any time without losing any information.

Daily Use: How to Start Conversations and Manage Chats and Groups

One of the advantages of SimpleX is its ease of use, despite the large number of advanced featuresStarting a chat is as simple as sharing your ID with the desired person. However, since it's for one-time use and temporary, no one will be able to find you later if they don't have your invitation active.

To start a chat:

• Invite your contact using a single-use link: Copy the link and send it through your preferred channel (email, another app, etc.).
• Invite via QR: Have your friend scan the code directly from their SimpleX app to establish the private and secure connection.

Once connected, Messages and files are transmitted end-to-end encrypted and only remain temporarily on the server until delivery.All content is protected on your device in encrypted format and can be accessed whenever you want.

In the case of groups, you can create a "secret group" and invite multiple users, or a private group that only you can use as a secure repository for confidential information. In both cases, all management is local and under your control, and all members enjoy the same guarantees of anonymity and encryption.

Privacy and Security Management: Tips and Best Practices

While SimpleX is designed to be secure by default, there are some recommendations to maximize your protection:

• Always verify public keys when connecting to a new user., even if you use links or QR, to avoid any possibility of MitM attacks.
• Carefully manage single-use invitations and group access; do not distribute links in public places.
• Keep the app updated, as security improvements and new features are often released frequently.
• If you're using the self-hosting option, configure your server properly and learn about administration best practices.
• Always use the encrypted database and export periodic backups to ensure the integrity of your data in case of device loss.

SimpleX has undergone independent security audits, which provides an extra level of confidence and demonstrates the project's seriousness in protecting user privacy.

Limitations and points to improve

Although SimpleX excels in many ways, it is important recognize some limitations detected by the community:

• Focused on small groups: Although automatic pool encryption is a benefit, SimpleX recommends that pools not be too large to maintain security and performance.
• Lack of advanced features compared to older apps: Some features present in XMPP, such as advanced font customization or direct integration with voice and video calls, may not be present yet or may require future updates.
• Relative youth of the project: Although SimpleX has already passed security audits and is evolving rapidly, it lacks the historical background of projects like XMPP, so some in the community are cautious about its long-term consolidation.

However, the speed with which new features are added and the transparency of development make SimpleX a project with very promising prospects.

With SimpleX Chat you have at your fingertips A messaging tool that is different and much more private than most current options., perfect for those seeking secure and anonymous communication as well as for those who demand the most customization and data control. Whether you're new to encrypted messaging or already have experience with other apps, SimpleX will surprise you with everything it offers and the peace of mind it brings to your digital life.