Backend engineer · Builder

From wiring buildings to wiring systems.

I'm Jared Lemler, a backend engineer and former electrician. I build practical systems with Python, FastAPI, Postgres, and Docker — federated platforms, data pipelines, and developer tooling that solve real problems.

Calm under pressure, obsessed with craftsmanship, and always looking for clearer, more honest systems.

View projects Read my story Resume

Currently

Building VoxPort Studio

Federated podcast platform on the AT Protocol — extraction worker, multi-env deploy, observability stack.
Shipping doc-lok

Zero-dependency npm package for condensing LLM context windows.
Learning

Podcasting domain internals, distributed systems, and AI-native dev workflows.

From electrician to backend engineer.

I started my career in construction and electrical work. I was coordinating with teams, reading plans, and wiring systems that had to be safe, reliable, and maintainable. That work taught me craftsmanship, patience, and how to stay calm under pressure.

Over time I got hooked on the logic behind automation and control systems. Eventually that pulled me into software. Now I use the same mindset to design APIs, databases, and services that solve problems for people instead of just chasing hype.

How I learn new domains

I pick up new domains fast. Podcasting pulled me in, and I taught myself how a platform actually works — RSS distribution, hosting economics, the AT Protocol as an identity and record layer — well enough to architect one. That's the pattern: get curious, learn the domain honestly, then build.

I care about honesty, ownership, and better systems. That shows up in the tools I use (Python, FastAPI, Postgres, ATProto), the projects I build, and the way I learn: in public, without pretending to have it all figured out.

Brand pillars

Craftsmanship: do it right, not just fast.
Purpose: build things that make life better.
Calm clarity: break problems into clear steps.
Independence: prefer open, user-owned systems.

Outside of code

I live in the San Francisco Bay Area with my wife and our dogs. Outside of work you'll usually find me gaming, hiking and exploring areas I haven't been, and going down rabbit holes of topics that are interesting and new to me.

What I'm good at.

Backend-first, with the toolchain and discipline to ship and operate it.

Backend & data

Python, FastAPI, Django
TypeScript, Fastify, Node.js
PostgreSQL, SQLAlchemy 2.0, Prisma
REST API design, auth (JWT), data modeling
Background jobs, ETL, real-time event processing
WebSocket consumers & backpressure
Pydantic validation, Alembic migrations
Pandas, CSV/JSON pipelines, batch processing

Systems & delivery

Docker & docker-compose
CI/CD: CodeQL, Gitleaks, Bandit
Observability: Sentry, OpenTelemetry, Axiom
Cloudflare R2, Fly.io, Neon, AWS (EC2, S3)
Testing with pytest / Vitest
AT Protocol & decentralized apps
Multi-env deploys (dev/staging/prod branching)
Structured logging & access-log monitoring

How I work

Breaks work into clear steps
Calm, honest communication
Strong bias toward learning
Docs as a progress compass: has agents maintain clean, detailed markdown — status, worklogs, plans — so project state is always legible to humans and the next agent.
AI-native workflow: treats agents as collaborators with structured handoffs, not magic buttons.
Learning out loud: writes to understand, not just to publish.

Projects that represent how I think.

Not toy apps. Real problems, real constraints, and systems I care about.

VoxPort – Creator tools on the AT Protocol

Fastify · Next.js · ATProto

Decentralized creator tools where podcasters own their identity, feed, and audience. Built on the AT Protocol with custom lexicons and a Fastify/Next.js stack to keep creator data portable and under their control. Also published an AT Protocol skill on skills.sh to help others build on the protocol.

Federated ingestion at scale: resilient WebSocket consumer with bounded memory backpressure (1,000-event cap) and 100-event batching — ~95% I/O reduction vs. per-event persistence.
Audio extraction worker: dedicated ffmpeg worker with SSRF guards, FOR UPDATE SKIP LOCKED job claiming, and Cloudflare R2 content-addressed storage.
Multi-env production deploy: API on Fly.io, web on Vercel, Postgres on Neon (dev/staging/prod branches), with Sentry + Axiom + OpenTelemetry observability.

Why it matters: I care about ownership and systems that don't trap people. This project pushes me to think beyond a single app and into protocols and ecosystems.

Try VoxPort →

Fastify Next.js ATProto

Travel Wishlist – Full-stack Travel Planner

FastAPI · React · Maps · Analytics

A real deployed app for saving, organizing, and analyzing travel. Combines a FastAPI/Postgres backend with a React frontend, including map views and basic analytics around visits and plans.

Full-stack architecture: FastAPI, PostgreSQL, and Docker with JWT auth, Pydantic validation, and a reusable CRUD service layer.
External API integration: city-based weather lookup with ~100ms response times, plus an interactive map layer for geographic visualization.
Calendar itinerary system: monthly/agenda views for trip planning with date-based organization of saved cities.

Why it matters: it's a complete loop — database design, APIs, frontend integration, deployment, and iteration based on actual usage.

FastAPI PostgreSQL React Deployable

doc-lok – Pre-prompt context condenser

TypeScript · Node.js · Zero-dep

A pre-prompt middleware that condenses link-bearing Markdown by resolving remote links into compact cryptographic markers — cutting context token consumption and API latency for LLM workflows. Published on npm with zero runtime dependencies.

Context window optimization: condenses prompt payloads by replacing unchanged remote Markdown links with compact <lok_id> markers, drastically cutting token usage.
Conditional caching pipeline: two-phase network verification using HTTP HEAD probes and If-None-Match ETag validation to skip unchanged resources.
Zero-dependency architecture: CLI and library built exclusively on native Node.js APIs — no third-party supply-chain risk, minimal cold-start overhead.

Why it matters: a focused, shippable tool that solves a real LLM-context problem with a craftsman's restraint — do one thing well, with no dependencies you don't need.

npm package → Source on GitHub

TypeScript Node.js SHA-256 ETag

Learning in public.

I write to document the journey from the trades to backend development, Docker headaches, and what I'm learning about building systems that last.

From Electrical Work to Software Development: Embracing Public Learning

Why I stopped hiding the messy part of learning and started sharing the process instead.

My Docker Learning Journey: Struggles, Headaches, and Small Wins

A straightforward look at what actually tripped me up with Docker and how I worked through it.

Newer writing on pckt.blog →

My latest posts live on pckt.blog. Read them there.