Delta Chat: an easy, useful, free (as in freedom), secure and sovereign chat

Delta Chat is a messaging application that, at first glance, looks like just another app. It has practically the same features as WhatsApp (except for calls and channels, for now). But its operation is radically different: it has no central server, depends on no company, and does not require a phone number. It is not a commercial service waiting for a financial return.

It runs on the standard email infrastructure (IMAP and SMTP), using end-to-end encryption (E2EE) based on Autocrypt/OpenPGP, which are standard, technically mature protocols.

In essence, Delta Chat turns email into a secure, federated, and decentralized messaging network. This means that any individual or organization can use their own email server to chat or rely on specialized servers called chatmail, which allow the creation of pseudonymous accounts with automatically generated credentials.

Because the network is decentralized, if one server goes down, the rest of the network keeps working: there is no single point of failure and no company controlling the entire system.

Delta Chat does not ask for a phone number or any personal data when creating accounts. With a chatmail server, the application automatically creates a random username and password, with no link to your real identity.

Its E2EE is fully standard and mature, and metadata is kept to a minimum. Combined with Tor or a VPN, it provides a much higher level of privacy than any commercial app. In fact, if an organization has its own server, messages between members of the organization do not even travel across the public internet.

WhatsApp, even though it uses Signal's protocol to encrypt messages, keeps all the metadata (who talks to whom, when, and from where), and it is managed by Meta, the same company that makes a living off exploiting personal data. This metadata is a gold mine of information that can be used for commercial or even military purposes.

Telegram, for its part, does not enable end-to-end encryption by default: regular chats and groups are "Cloud Chats" where messages are stored on its servers to allow synchronization. Only Secret Chats 1:1 and calls are E2EE. In other words, Telegram can read the vast majority of messages on the network. Whether they share them with third parties is purely a matter of trust.

Delta Chat's security protocol is very robust, but it does not implement "perfect forward secrecy (PFS)", a feature that Signal does offer.

In practice, this means that if an attacker obtained the private key from your device, they could read past messages. Even so, for most personal or organizational uses this risk is minimal, and the advantages in autonomy and resilience far outweigh this technical limitation. A good strategy to mitigate this point with Delta Chat is to minimize how long messages stay on the server or on devices.

In Delta Chat, if a server is attacked or goes down, only its users are affected. The rest of the network keeps operating normally. Each group or entity can set up its own server, even on a home computer or a shared cloud for less than 10 EUR per month. That makes Delta Chat an extremely resilient network, capable of withstanding censorship, outages, or nationwide blocks. In case of an attack, launching another server is not hard; the only inconvenience is that the keys would have to be shared again.

Adding Delta Chat to another device is surprisingly easy: just scan a QR code to transfer the keys and configuration. This is possible because messages can remain encrypted on the chatmail server for a while.

One of Delta Chat's great advantages is that it can run on any existing email server.

A university, cooperative, or NGO that already has an email server can use it for Delta Chat without deploying anything new. This is extremely appealing.

This simplifies integration and reduces costs, but you also need to consider the email server's security: if that server is compromised or keeps copies of the messages, some privacy can be lost. It takes a bit of judgement to decide whether to use an existing email server, a chatmail server installed specifically for chatting, or a third-party chatmail server (there are several free ones). In any case, the three options are very secure and perfectly adequate for the vast majority of contexts.

The chatmail servers optimized for Delta Chat are the best option: they do not store messages after delivery, offer anonymous sign-up, and minimize the attack surface. In any case, the user can choose maximum convenience or maximum privacy within the same open ecosystem, always with a high level of security.

Telegram and WhatsApp copy our contact lists to make it easy to find our friends and facilitate communication. That is convenient, but it means handing over the information about our entire social network to private companies that pursue profit and, generally, have few scruples.

To avoid this problem, Delta Chat lets you share addresses and encryption keys using QR codes or links. The safest way is to meet in person and scan each other's QR codes with your phone. Another, more convenient option is to send the links through another channel. For example, I could send my WhatsApp contacts a message with the link they need to reach me on Delta Chat. I could also post the QR code on social media or on my personal website. It all depends on the level of anonymity you want to maintain.

• It does not yet offer public channels like Telegram's, but that is in development.
• It lacks PFS, which makes it slightly less secure than Signal in high-risk contexts. I do not believe this affects the vast majority of users.
• It has a small user community, which hinders its initial expansion. With patience and persistence we can change that.

Both Meta and Telegram bear enormous costs to maintain their servers, bandwidth, and global infrastructure. Until now, they have operated thanks to massive investments and venture capital, but that money has to be recovered. The inevitable outcome is what many call enshitification: a progressive degradation of the service to monetize it: more adverts, more data collection, premium features, artificial limitations, and less privacy.

This drift is structural: when a centralized company has the power and the need to monetize a user network, the service stops serving the user and starts serving the shareholders. Sooner or later, the cow has to be milked, and we are already seeing that with WhatsApp and Telegram.

Delta Chat, on the other hand, cannot be enshitified because it belongs to no one. It is free, distributed, community-driven software. No company can degrade it, sell data, or shut it down unilaterally. States would face an uphill battle dismantling the network (even though it does have a few weak points).

Delta Chat is not just an application: it is a way of understanding the internet that is very different from what we have accepted from Silicon Valley. It revives the original spirit of the internet: federated, open, and self-managed, while using modern technology and top-tier encryption. It is a tool that respects the freedom and dignity of individuals and communities and allows us to build sovereign, ethical, subsidiary, and resilient communication.

Installing Delta Chat is as easy as downloading the app from https://delta.chat/en. In under two minutes you can create an account, test it with a friend, and, if you have the technical skills, set up your own chatmail server.

You can also add your account to multiple devices simply by scanning a QR code.

The future of communication does not have to be in the hands of large corporations or servers located in California or Dubai, owned by companies that see us as a product rather than a client. Communication can be federated, open, and community-driven. Delta Chat reminds us that it is possible to have the early internet back without sacrificing convenience or ease of use. Communication can once again serve people, not the other way around.

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