Delta Chat

Secure decentralized messaging across all major platforms. Instant and reliable via fast chatmail relays, compatible with classic email providers. Features secure mini web apps for fun and collaboration, end-to-end encrypted and with P2P realtime channels. Security-audited multiple times.

Public Key

npub1lk4qv5hd50c4u9z9kdy53h45dyu3mq9v0qvx0k0ar348703dw2ystl3m2p

NIP-05 Address

delta@chaos-social.mostr.twinkle.lol

Profile Code

nprofile1qqs0m2sx2tk68u27z3zmxj2gm66xjwgaszk8sxr8m873c6nl8ckh9zgpz3mhxue69uhhyetvv9ujuerpd46hxtnfduqs6amnwvaz7tmwdaejumr0ds6amfuz

Publishing to

relay.damus.io

nos.lol

Author Public Key

npub1lk4qv5hd50c4u9z9kdy53h45dyu3mq9v0qvx0k0ar348703dw2ystl3m2p

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Last Notes

2026-06-09 19:58:47 UTC

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@nprofile…vqmm it's using WebRTC with mandatory end-to-end encryption which internally gets negotiated through end-to-end encrypted chat signalling messages.

2026-06-09 19:46:26 UTC

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@nprofile…6eda best place to ask and get more background is https://support.delta.chat
Also in the FAQ there is info like on channels: https://delta.chat/en/help#channels

2026-06-09 10:50:13 UTC

2.51+ releases are rolling into stores: Video/Audio Calls and Channels are not experimental but part of the default feature set now 💫
Calls and channels are always end-to-end encrypted, and only you and your contacts know each other's identity and metadata (avatars, names, keys etc.)
For calls, Delta uses a minimal Rust WebRTC turn server https://github.com/chatmail/chatmail-turn#turn-server-for-chatmail-relays running on hundreds of relays worldwide. It helps to establish P2P media streams, or for relaying traffic if P2P connections fail.
https://assets.chaos.social/media_attachments/files/116/719/712/793/843/004/original/c9abf7d1241cdbe9.png

2026-06-04 11:47:32 UTC

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@nprofile…8dhc The relay list should synchronize between the devices automatically. If this did not work, maybe try to add a relay from the other device and check if this is synchronized the other way round.
It is fine to try deleting the relay and trying again, but don't delete the first relay that is the only shared relay between the devices, they need at least one shared relay to be able to communicate and sync the relay list.

2026-06-04 10:24:51 UTC

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@nprofile…8dhc your other devices need to be at least v2.33 to synchronize your relays. Maybe the MacOS client needs to be upgraded?

2026-05-27 17:37:13 UTC

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@nprofile…jxg0 wir nutzen es selbst viel, und kennen auch viele, die das tun. Im chatmail-relay netzwerk gibt es kaum Probleme mit der Nachrichtenzustellung. Bei klassischen email providern gibt es spam-filter oder configs, die die Nachrichstenzustellung unsicher machen koennen, abgesehen von fehlenden Push notifications. Es ist natürlich nicht auszuschliessen, dass es bugs gibt, gerade auch bei Calls auf bestimmten Geraeten, aber das wird eher auf https://support.delta.chat diskutiert.

2026-05-27 06:51:06 UTC

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@nprofile…58ej There is documentation about various areas of the project, what exactly are you looking for? https://cosmos.delta.chat/ gives an overview about the components of the ecosystem. We also plan to publish a security whitepaper later this year, if that's your angle.

2026-05-26 21:31:02 UTC

Reminder: There are no accounts in the classic sense anywhere with #chatmail or #deltachat.
It's all private profiles on end user devices which co-ordinate in a #p2p fashion. Chat profiles *use* email (relay) addresses for transporting messages through a federated e2ee-restricted SMTP network.
A chat profile or chat group has zero data on the server. It's radically different from classic email servers, Whatsapp, Signal, XMPP and Matrix servers which host and control chat identity.
https://assets.chaos.social/media_attachments/files/116/643/000/131/217/285/original/d3ba9a418234ea6f.png

2026-05-22 18:38:59 UTC

The tale of "convenience" is a bit of a trick. A lot of corporate provided services maybe were somewhat convenient a decade ago, but they are now increasingly authoritarian, and people tend to ignore how much time they steal.
Total number of hours spent solving captchas or consent screens with #deltachat #chatmail and #webxdc apps: 0 (zero). Nada. Zilch.
Compare with the estimated 819 million hours which humans spent with Google's recaptcha alone https://boingboing.net/2025/02/07/recaptcha-819-million-hours-of-wasted-human-time-and-billions-of-dollars-google-profit.html

2026-05-19 19:37:53 UTC

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@nprofile…r5fw Hi :) you need to turn on "Debug Calls" in the "Advanced > Experimental Features" settings, then they should work, on all platforms. If they do not work, please open a bug report on https://github.com/deltachat/ - they are about to become un-experimental very soon.

2026-05-15 13:56:02 UTC

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@nprofile…v5xn not sure and probably best to discuss in the forum where there are at least related topics.

2026-05-14 20:28:50 UTC

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@nprofile…7n40 sorry but it's not clear what wording you are refering to precisely. pull requests can be opened at https://github.com/deltachat/deltachat-pages/blob/main/en/help.md and then more properly discussed by the people who care for this page.

2026-05-14 20:14:07 UTC

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@nprofile…7n40 We are doing our best but mistakes like a wrong link or a misleading link happen.
In the fediverse and support forum, we have otherwise linked to the security FAQ section many times.
What is likely missing more than refining the FAQ entry, is a comprehensive security paper, linking and putting the audits in context, and giving 10-15 pages of going into some details, threat models etc.

2026-05-14 18:27:21 UTC

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@nprofile…7n40 ups, thanks for pointing a bug in our home page! You are totally right to criticize that audits are not the same as security analysis.
The "audited end-to-end encryption" link should actually go to:
https://delta.chat/en/help#security-audits
It's also fixed on https://delta.chat now.
Status: there are 5 published independent audits and one published security analysis from the ETH Applied Crypto Group. There is another soon to be published audit, and more audits scheduled this year.

2026-05-14 11:16:35 UTC

Good news among the bad news!
If the recent #0day attacks against Linux kernel+servers were launched against #chatmail relays, privacy of chatting with #deltachat is preserved. Why? Because we already assume the server could be actively hostile, and still not read or see any avatar, names or messages.
Since the March 2.48 zero-metadata releases relays/servers do not see cryptographic identities, and get no chance to launch "machine-in-the-middle" (MITM) attacks.
https://delta.chat/en/2026-03-31-zero

2026-05-08 19:12:28 UTC

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@nprofile…jcvg Since version 1.10.0 of chatmail/relay (https://github.com/chatmail/relay/releases/tag/1.10.0) this should not be necessary because of the change that removes more messages when mailbox is about to run out of space.

2026-05-08 12:07:09 UTC

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@nprofile…9gsf @nprofile…85zd very interesting, thanks! Indeed lateral thinking with withered technology is very close to what we are trying to do ...

2026-05-05 19:22:58 UTC

We don't think any institution or state has the right to prevent families and friends from private chatting, physically or digitally. But the Cyber Authority China (CaC) seems to take offense:
- they made Apple remove #deltachat iOS for mainland china
- their great firewall appears to block some #chatmail relays
- if you ask DeepSeek directly about Delta Chat, it doesn't want to talk
It's pretty sad, really. Everybody on this planet needs, and has a human right to private communication.
https://assets.chaos.social/media_attachments/files/116/523/548/441/767/249/original/ad53d7ff60ee21bc.png

2026-05-05 11:07:27 UTC

Congrats to #protonmail for beating us on introducing Post-Quantum Cryptography into mail messaging!
No worries. We'll implement https://autocrypt2.org which additionally offers reliable deletion / forward secrecy during 2026 :)
We are working with Proton cryptographers on OpenPGP specifications, and they are now moving towards using @nprofile…pngr , the end-to-end encryption we are using.
Everything will be based on RFC9580 (#OpenPGP v6) ... the eocsystem is moving :)
https://proton.me/blog/introducing-post-quantum-encryption

2026-05-05 10:54:52 UTC

Ok, #protonmail beat us on introducing PQC cryptography, but we'll beat them on Reliable Deletion

2026-05-02 21:42:13 UTC

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@nprofile…vr2t @nprofile…zqdw it's fine to call us out on the mixing of concerns. It was actually meant to direct some attention to other projects and not just put us in the center, but it also was confusing the message a bit, hopefully now sufficiently clarified. Let's maybe not discuss this here further if you can agree -- we can always open a chat group ;)

2026-05-02 18:19:09 UTC

All of the advances in #deltachat apps and the growth of the #chatmail relay network, wouldn't be possible without public funds and private donations, an estimated 800K EUR in 2026 ❤️ money goes to ~16 FOSS contributors with no money left for president, board or director salaries 🖤
Signal uses >50 Million per year, Telegram and Whatsapp 100's Millions, and they are all not building permission-free decentralized chat infra and apps, let alone secure mini app ecosystems https://webxdc.org

2026-05-02 16:54:38 UTC

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@nprofile…4u7t @nprofile…u9q8 @nprofile…c5mx
chatmail relays, and the associated email infrastructure, are evolving quite a lot but we don't post much about it here. #chatmail infrastructure also is the *core Rust library* which is used by all the clients, so it's not just the "server" side. See also https://chatmail.at
https://assets.chaos.social/media_attachments/files/116/506/011/772/876/563/original/250d7caafc40de2a.png
https://assets.chaos.social/media_attachments/files/116/506/018/680/153/355/original/40798d876241e659.png

2026-05-02 13:56:58 UTC

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@nprofile…v5xn @nprofile…u9q8 @nprofile…zqdw @nprofile…c5mx we edited the post to be clearer about the fact that neither Delta Chat nor the other chatmail clients are receiving funding. The chatmail infrastructure consists of "relay" setup templates and the "core chatmail library" that is used by all clients. More here https://chatmail.at

2026-05-02 13:48:45 UTC

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@nprofile…zqdw sorry. we edited the original post, reads clearer? Otherwise drop a DM but please keep in mind we have a 500 char limit and dopn't want to rewrite the whole post :)

2026-05-02 13:30:24 UTC

We’ve been busy building and releasing but it’s high time to share some major news: @sovtechfund is investing nearly €500K into #chatmail
This 18-month commitment supports chatmail maintainers keeping the core infrastructure secure and evolving, which is the backbone for:
#DeltaChat
@arcanechat
@nprofile…u9q8
Parla on Gnome (cc @nprofile…zqdw )
and many chat bots
A huge thank you to the Sovereign Tech Fund for investing in open, secure and decentralized communication!
https://www.sovereign.tech/tech/chatmail

2026-04-29 15:44:49 UTC

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@nprofile…q8z8 can you DM us the IP addresses it tries to connect to? It should only try to connect to your mail servers/relays and nothing else.

2026-04-26 05:27:03 UTC

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@nprofile…sqwl it was about #chatmail relays https://chatmail.at/relays

2026-04-25 21:24:43 UTC

"it's always the receiver that determines the meaning of a message" is a famous opening quote at the first symposium on self organizing systems in Chicago, 1959. This and many other findings from those circles re-appear in our day to day discussions.
We are doing next steps towards automating planet-wide decentralized onboarding, including in Internet islands, without resorting to a central list of relays. Good news: we have now officially lost track of even the number of existing relays 😂

2026-04-25 16:48:28 UTC

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@nprofile…v5xn thanks for the pointer. we are indeed following rollout of formats as "Jpeg XL". while bigtech support has surged recently, we still have to support lots of older devices that don't support it natively yet and would require additional effort or have poor performance. for that reason, it's not a priority just now, but we’re keeping a close eye on it.

2026-04-23 15:16:09 UTC

Making sure that deleted messages are actually deleted and unrecoverable is more involved than most folks think. The FBI could recently recover deleted Signal messages from an iOS phone because the notifications you see on your phone were stored in an extra database. Apple has now fixed this, also making #deltachat iOS users safer. Few know that so called "forward secrecy" is all about deleted messages becoming unrecoverable, see https://autocrypt2.org for our plans
https://www.heise.de/en/news/FBI-extraction-of-deleted-Signal-messages-Apple-secures-iPhones-better-11269038.html

2026-04-22 22:04:46 UTC

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@nprofile…cq3m it's usually better to find a phone-wide solution to protecting individual app access. Moreover, there are many real-world threats where an app lock does not help at all, unfortunately. FWIW you can backup your account to a file, store it remotely, delete Delta Chat, and and re-instate it all later when needed and safe again. To discuss this more in depth, it's better to move to the https://support.delta.chat

2026-04-22 16:36:41 UTC

#deltachat user profiles are private and invisible to the public. No one can discover you, or your children, via phone numbers or any other public handle. Chat profiles exist only on user devices. No PIN and no "SMS verification code" ever asked or needed.
The lack of "public discovery" also means you don't auto-discover others via phone numbers or other public handles. Getting in contact with others is "opt in": you scan a QR code or click an invite link to join a group or open a chat.

2026-04-22 08:15:26 UTC

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@nprofile…4sxc we strive towards making relay selection completely automatic, but for now we want to make sure it works at all, and smooth around the edges ;)

2026-04-22 04:16:11 UTC

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@nprofile…3jrm If you add multiple relays to your profile and change between them, you will appear as the same contact, both in 1:1 and group chats. Internally since Delta Chat v2 all contacts in encrypted chats (the ones not marked with an envelope icon) are identified by their OpenPGP key, and it does not matter from which email address the message arrives, so when you switch to another address your contacts will likely not even notice unless they look in debug info.

2026-04-21 22:57:09 UTC

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@nprofile…3jrm You can switch the sending relay at any time. If you send a message and sending gets stuck because the sending relay is not reachable, you can select another relay for sending and keep sending messages. There is no automatic "failover" yet.

2026-04-21 17:02:40 UTC

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@nprofile…8dhc Go to your existing profile. Settings. Advanced. Relays. And add a relay there.

2026-04-21 16:49:18 UTC

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@nprofile…8dhc the instructions were about adding a second relay. In the screen you posted you can just create a profile and then go to advanced settings.

2026-04-21 16:06:25 UTC

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@nprofile…8dhc Are you doing this on the phone or on desktop?
From Android, if you go to the second relay page (https://mehl.cloud/) and click on the QR code (with the "Einen kostenlosen Email-Account bekommen" alt text), this will open Delta Chat, possibly ask you to unlock the phone, and add a relay to the currently selected account.

2026-04-21 15:59:40 UTC

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@nprofile…65e6 using two relays means that it works when either one of them works. When one fails, the other can still be used for chatting. It does not introduce a dependency but makes your more independent from any single server.

2026-04-21 14:39:19 UTC

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@nprofile…65e6 You can use your own mailbox on a non-chatmail server if you want. If you are sure it works reliably all the time, you also don't need multiple mailboxes. You can also add chatmail mailboxes next to non-chatmail ones if you want to have things working when your server is down but chatmail relay you added works.

2026-04-21 13:42:40 UTC

This morning nine.testrun.org was briefly unavailable, some network problem. A good time to remind everyone to add a second relay to your #deltachat app:
1. Go to https://chatmail.at/relays randomly choose one of the listed relay pages and copy the invitation code to your clipboard
2. In delta chat settings go to advanced/relays and tap "add relay" and paste the invitation code
3. That's it.
If one relay is unavailable you still can receive and send messages.
https://delta.chat/en/2026-03-31-zero#maximizing-availability-and-resilience-through-multi-path-delivery

2026-04-18 12:47:10 UTC

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@nprofile…sr57 new releases are rolling 2.49 bug fixes mostly. Well see what next releases bring :)

2026-04-18 12:33:14 UTC

"Popularity is overrated" is an often occuring phrase in our circles. Which is of course nonsense because only what is popular, counts, right? Only what everybody else does is a valid choice, right? #deltachat #chatmail and #webxdc are used in private places and communities that people are molding for themselves. We are just providing tools and approaches that work ... At least most of the time 😅 "Nothing works all the time" is another project mantra. Brb preparing the next releases :)
https://assets.chaos.social/media_attachments/files/116/425/711/182/781/916/original/5da9f9b36a9fb34f.jpg

2026-04-17 19:19:14 UTC

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@nprofile…vhxg currently 2.49 begins rolling (bug fix releases) and then channel improvements are "ASAP"/ next release :)

2026-04-13 09:23:06 UTC

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@nprofile…szsq actually, if you ask so directly: we've heart rumors of a web client beginning to work, but it's a very wild project we won't point to, yet. Quite obviously,. there are challenges around E2EE and security when doing a chatmail web client. Stay tuned :)

2026-04-13 08:14:27 UTC

Apart from the new #Gnome effort, there also is an interesting experiment of a #Rust terminal-client with #Ratatui -- for others to start from should they feel they need some enjoyable distraction :)
https://git.sakamoto.pl/j-g00da/deltarat-experiments
#Chatmail clients typically use the Rust core library which provides all networking, cryptography, persistence, real-time networking, mail relay/server interop. Documentation to help with writing clients is scattered, but at least there are plenty examples to learn from.

2026-04-11 14:22:04 UTC

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@nprofile…hca9 did you try enabling "Debug Calls"? See also https://delta.chat/en/2026-03-31-zero#native-calls-on-android-and-ios

2026-04-11 13:43:07 UTC

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@nprofile…dnwg fixed, thanks.

2026-04-11 13:39:53 UTC

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the public #chatmail relay list https://chatmail.at/relay covers about ~20% or so of chat relays we heart about and have traces or hints from, and we definitely don't see everything -- which is how it should be :)

2026-04-11 13:27:16 UTC

What if all public funding and all private donations to our efforts stop tomorrow?
Users should be fine for years thanks to the wonderful world-wide community of #chatmail relay operators 💜 Relays are dirt cheap to run. Also, our developments are much cheaper and less complex compared to what we know from comparable efforts.
No worries though!
We currently have moneys to help sustain ~15 contributors, with a sum similar to what other projects pay for their foundation president/CEO alone :)

2026-04-11 05:44:03 UTC

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@nprofile…dmmg true story: we regard German train rides and using wifi there as a good test bed for our networking code's ability to work in slow and malfunctioning networks. For example two travelling contributors messaged and established p2p realtime networking between two high speed running ICE trains, to test robustness and reconnection fitness :)

2026-04-09 15:31:46 UTC

Do you want to live in a world where private digital communication is not possible anymore? That's a growing reality for many people world-wide.
Private communication is extremely important to salvage into the digital realm and it's not just about encryption, but about the ability to choose your own identities privately, without state sanctioning.
It needs caring for solving real problems, in real implementations, for real people, and not just some riding on grand ideas. Just saying :)

2026-04-09 12:40:58 UTC

#deltachat contributors range from age 16 to 65, spanning diverse genders and even more countries and cultures. We have many discussions, and also conflicts but we usually don't carry those out in big public groups but rather go for 1:1s and generally small-group discussions. There is no central assembly or board that decides everything. It's more chaotic and admittedly hard to get an overview on, but thats' also how the yearly #CCC congress comes about, which many of us regularly attend.