experintellia.
Agentic coding experiments · since Apr 2026

How far can agentic coding go?

These repos are my answers so far. Mostly webxdc apps that run offline inside chats, plus a Delta Chat fork that runs entirely in the browser.

github.com/experintellia
Projects

The big ones

The two biggest efforts: a Delta Chat fork with its own patch stack, and a dead game brought back to life.

slothfulchat-web

A feasibility prototype: a Delta Chat fork that runs standalone in the browser

The chatmail core compiled to WebAssembly, driving the Delta Chat Desktop frontend as an installable PWA. It's also a base for features of its own, in the spirit of forks like ArcaneChat.

  • 1:1 audio, video and screen-share calls in the browser, wire-compatible with Delta Chat
  • Pick a chatmail relay at onboarding, with live reachability and latency
  • Tracking parameters stripped from links; opt-in previews rendered on the sender's device
  • Animated Telegram stickers, per-chat HTML export, :emoji: completion
  • Installs to the home screen on iOS and Android
  • Rust → WASM
  • PWA
  • chatmail
Open web app View repo
web.slothful.chat
slothfulchat-web in a desktop browser: chat list on the left, a group chat with a shared photo and reactions on the right slothfulchat-web in a desktop browser: chat list on the left, a group chat with a shared photo and reactions on the right
The same group chat in the installed app on a phone The same group chat in the installed app on a phone

Data Dealer

A satirical privacy game, playable again

You run a shady data-broker empire and learn first-hand how personal data gets harvested, traded and abused. The original needed a game server that's long gone. This port revives it as a fully standalone webxdc app: no server, playable offline inside the chat.

  • Rebuilt for phones, down to 375 px wide
  • English and German, switchable mid-game
  • 800+ unit tests plus Playwright end-to-end tests on every PR
  • .xdc
  • Port
Play in browser View repo
Data Dealer game screen
webxdc mini apps

Apps you send into a chat

Each one is a single .xdc file. Drop it in a group on Delta Chat and everyone uses it together. No accounts, no server, and it works offline.

Jun 2026
MD-Docs editor with live markdown preview

MD-Docs

md-docs.xdc
Repo

An Obsidian-style markdown editor. Everyone in the group edits the same document live.

  • CodeMirror 6
  • Yjs
27 Jun
Grocery Board in Columns view, items sorted into aisle sections

Grocery Board

ordered-shopping-list.xdc
Repo

A shared shopping list that sorts itself into store aisles. Fix an item's aisle once and it's fixed for everyone. Switch between a List and swipeable Columns.

  • Yjs
27 Jun
Jul 2026

Chess Tournament Early prototype

chess-tournament.xdc
Repo

Many games at once in one chat, with a lobby, standings and live spectating. Standard chess plus eight variants, and a Stockfish opponent. Built as a one-shot test of an agent setup.

  • chessground
  • Stockfish WASM
14 Jul
Aug 2026
Halvsies expense list grouped by day with each person's share

Halvsies

halvsies.xdc
Repo

Split a bill in the chat, settle it in as few transfers as possible, then pay in a tap: payment links with the amount pre-filled, IBAN details and EPC QR codes.

  • EPC QR
2 Aug
Misc

Smaller things

Tools, components and data mirrors, some spun out of the bigger projects.

DeltaChat Changelogs viewer

DeltaChat Changelogs

A fan-made changelog viewer for the Delta Chat ecosystem: Desktop, Android, iOS, DeltaTouch, Core, Parla, Chatmail Relay and ArcaneChat. Pulls changelogs live from GitHub and Codeberg, with per-client tabs, search and a scroll-spy TOC.

Open site

basicwebrtc WIP

Self-hosted video calls for 1:1 or small groups, encrypted and peer to peer. My fork reworks most of the call experience:

  • Lock a room: newcomers knock, and anyone inside lets them in
  • A lobby with camera preview and mic test before you join
  • In-call chat, and an end page with the call summary and a "Copy chat" button
  • Dark mode, a keyboard-friendly call bar, and calls that recover when the network drops
  • 160 tests, 120 of them end to end, plus cross-browser calls with Firefox and Safari in CI
  • WebRTC
  • Fork
Repo

lyrics-component

A karaoke-style lyrics view that follows playback, and an editor to sync your own lyrics to the song. Lyrics only come from you, never from an online lookup.

  • Karaoke down to the word: each word fills in as it's sung, right to left in RTL text
  • Sync by tapping Stamp as each line starts, then each word, with the line on loop
  • A tape-style waveform you drag to scrub, with verses and choruses as coloured bands
  • Paste or load LRC and keep its timing; export TTML in the shape Apple Music uses
  • Keyboard shortcuts for stamping and 10 ms nudges, with undo across every step
  • React
  • LRC
  • TTML
Open editor

chatmail-relays-mirror

A daily, machine-readable JSON mirror of chatmail.at/relays with CORS enabled, so browser apps can read it. It powers slothfulchat-web's relay picker.

relays.json

What's different in slothfulchat-web

A curated pick from the patch stack on top of chatmail core and Delta Chat Desktop. Upstream code is never edited in place; every change is a separate patch.

Running in a browser

  • chatmail core compiled to WebAssembly. Mail traffic tunnels through a WebSocket bridge, and TLS ends inside the browser, so the bridge only sees ciphertext.
  • Encryption runs in background workers, so the app stays responsive on phones.
  • Large attachments download in chunks with progress, and resume after a reconnect or reload.
  • madmail servers work with no bridge at all, over plain HTTPS (experimental).

Calls & media

  • 1:1 audio, video and screen-share calls, compatible with the Delta Chat apps.
  • Animated Telegram stickers.
  • A video player with hotkeys and a floating mini player; custom voice-message controls.
  • Export a chat as a self-contained HTML viewer plus its media.

Privacy

  • Tracking parameters like utm_* are stripped from links.
  • Opt-in link previews, rendered on the sender's device so recipients never contact the site.
  • Grammar and spelling check, on-device with Harper or through LanguageTool.

Chatting

  • :emoji: and /bot command completion in the composer.
  • Telegram-style reply threads (experimental, opt-in).
  • Click a reaction to join it; reactions right in the message menu.
  • Unread-only filter, a resizable chat list, and an estimated time-to-read on unread badges.

Onboarding

  • Choose the chatmail relay for a new profile, with live reachability and latency.
  • Add more relays from a list, by scanning a contact, or by typing a domain.

Not in this build (yet)

  • webxdc apps (planned)
  • Second-device transfer; file backups cover moving a profile
  • Maps and location streaming
  • Database encryption
Full patch list on GitHub