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
I think Anthropic and OpenAI have found product-market fit
<p>Anthropic are <a href="https://techcrunch.com/2026/05/20/anthropic-says-its-about-to-have-its-first-profitable-quarter/">strongly rumored</a> to be about to have their first profitable quarter. Stories <a href="https://www.theinformation.com/
SIMONW · 29m 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· 29m ago↑ HOT
I think Anthropic and OpenAI have found product-market fit
68
aidevLOB· 1h ago↑ RISING
A brief note about slot access cost in Common Lisp
62
devsystemsLOB· 1h ago↑ RISING
Interview with Zig creator Andrew Kelley
62
devsystemsVERGE· 7m ago↑ RISING
The Verge’s 2026 college graduation gift guide
42
techTC AI· 1h ago↑ RISING
AI coding startup Cognition raises $1B at $25B pre-money valuation
56
aitechVERGE· 11m ago↑ RISING
You can print, slice, and engrave using this desktop crafting machine
42
techsystems✦ /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






