A deep dive into SpacetimeDB's TypeScript SDK and how to wire it into a Next.js 15 App Router application for live visitor tracking and realtime features.
3 min readCurrent systems
Active work,
live signals, and writing.
Featured builds, the latest ranked signal, and recent writing — all in one place.
Featured build
MAINFRAME
Open-source bash stdlib for AI agents. Signals systems-level engineering range. Shows open-source authorship.
Pure bash runtime · Agent working memory primitives
Latest ranked signal
Count the number of Safari tabs
<p>Tiniest TIL, using AppleScript to count the number of open browser tabs in Safari:</p> <pre><code>osascript -e 'tell application "Safari" to count tabs of every window' </code></pre> <p><img alt="I ran it in a terminal window and got back 370
SIMONW · 1h ago · score 68
Publishing system
Building Realtime Apps with SpacetimeDB and Next.js 15
A deep dive into SpacetimeDB's TypeScript SDK and how to wire it into a Next.js 15 App Router application for live visitor tracking and realtime features.
3 min read · spacetimedb · next.js
Open-source ecosystems
Projects I support
Small but important signal: I contribute to and support AI-native developer tooling beyond my own products.
✦ Selected Work
Systems I've Built
Ranked signal feed
Full feed →SIMON· 1h ago↑ HOT
Count the number of Safari tabs
68
aidevVERGE· 7m ago↑ RISING
Tidal won’t pay royalties on AI-generated music but isn’t banning it outright
42
techaiHF· 1h ago↑ RISING
DiScoFormer: One transformer for density and score, across distributions
64
airesearchTC AI· 1h ago↑ RISING
Anthropic and Gov. Newsom forge deal allowing California government to use Claude at half price
56
aitechTC AI· 1h ago↑ RISING
South Korean tech giants commit over $550B to ease ‘RAMageddon’
56
aitechMIT TR· 1h ago↑ RISING
AI agents are not your “coworkers”
57
researchai✦ /now
What I'm Doing
Right Now
Building
ACTIVE
PropertyJunk.com — junk removal SaaS platform
ACTIVE
TaxScout.app — commercial real estate tax optimization
WIP
MAINFRAME — open source bash stdlib expansion
WIP
toddwatts.dev — this site
Reading
01Attention Is All You Need (re-read)
02The Pragmatic Programmer — 2nd ed.
03Designing ML Systems — Chip Huyen
Watching
▶
Andrej Karpathy
Neural nets: Zero to Hero
▶
Lex Fridman
Sam Altman ep.
▶
ThePrimeagen
Rust streams
My Setup
EditorVS Code + Claude Code
AIClaude Sonnet 4.5, Pi
RuntimeBun 1.2
DeployVercel






