JONAS STAMM
— FIELD NOTES
AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building ·AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building ·AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building · AI Engineering · Growth Hacking · Startup Building ·
technical-deep-dive— Featured · Aug 31, 2026

The hard part of a tender radar is not the matching

Most of the work in shipping BauGPT's Ausschreibungs-Radar had nothing to do with matching. Deciding whether a public tender fits a Bau company's profile was th...

Read the essay 7 MIN READ · Nº 01
FEATURED ESSAY
No. 01 · technical-deep-dive
KEY INSIGHT
Most of the work in shipping BauGPT's Ausschreibungs-Radar had nothing to do wit
RUN TIME
7:00
CHAPTER 01
Latest field note

Latest articles

24 OF 24 · UPDATED 31 AUG 2026
SORT:  | 
technical-deep-dive · Aug 24, 2026
01

The hard part of a tender radar is not the matching

Most of the work in shipping BauGPT's tender radar had nothing to do with matching. Matching worked early and was never the risky part. Everything after that wa...

7 MIN READ
technical-deep-dive · Aug 20, 2026
02

What Bau Enterprises Actually Made Us Build

Most of what we shipped on BauGPT in the last weeks had nothing to do with the model. It was folders, permissions, single sign-on, and Word files that open corr...

7 MIN READ
technical-deep-dive · Aug 20, 2026
03

Wide tables, umlauts, and who is allowed to write into a folder

If you want to know whether an AI product is really running inside a construction company, don't ask about the model. Ask what broke last week. For us the answe...

7 MIN READ
build-in-public · Jun 1, 2026
$ we run ai agents inside baugpt.
# build-in-public
read-time: 7min

We run AI agents inside BauGPT. Here's what it taught us about building them.

We build AI for the construction industry. We also run AI agents inside our own company to handle scheduling, ticket routing, code review, and content ops. That...

7 MIN READ
product · May 21, 2026
05

Our enterprise onboarding takes 90 minutes. The procurement took 11 weeks.

A construction company with a four-billion-euro annual turnover signed up for BauGPT last quarter. Their procurement process took eleven weeks. The actual onboa...

4 MIN READ
product · May 21, 2026
06

We process 40,000 WhatsApp messages a week. Here's why we built there.

BauGPT processes 40,000 WhatsApp messages a week. About 40% of them are voice notes. I mention this not to flex on a number. I mention it because it explains ev...

4 MIN READ
Build in Public · May 12, 2026
07

AWS Amplify PR Preview Links in 15 Minutes

AWS Amplify PR Preview Links in 15 Minutes Why this matters Your team opens a frontend PR. The reviewer has to either: - Check out the branch locally (5-10 min...

3 MIN READ
ai-engineering · Apr 27, 2026
08

How I Built a Personal CRM with AI (Because I'm Bad at Remembering People)

I'm bad at keeping track of people. Not in a rude way — I genuinely like meeting people — but after a coffee with someone interesting, I'd forget half the conve...

4 MIN READ
build-in-public · Apr 26, 2026
$ the app store rejection playbook
# build-in-public
read-time: 5min

The App Store Rejection Playbook

We got rejected three times before BauGPT Mobile went live. Not for bad UX. Not for crashes. For policy violations we didn't even know existed. Here's what we l...

5 MIN READ
ai-engineering · Apr 19, 2026
10

How RAG Beats Fine-Tuning for Most Startups

How RAG Beats Fine-Tuning for Most Startups When we first started building BauGPT, I was convinced we needed to fine-tune our own model. I mean, it sounds so c...

4 MIN READ
growth-stories · Apr 19, 2026
11
growth
vs.
the default

Why WhatsApp Is the Best Growth Channel for B2B (And How We Use It at BauGPT)

Why WhatsApp Is the Best Growth Channel for B2B (And How We Use It at BauGPT) Most B2B founders follow the same playbook. You get on LinkedIn, you post every da...

4 MIN READ
ai-engineering · Apr 19, 2026
12

The Nightmare of Optimistic UI in Chat Apps (And How We Fixed It at BauGPT)

The Nightmare of Optimistic UI in Chat Apps (And How We Fixed It at BauGPT) Users are spoiled. 🤣 If you click "send" in a chat app and see a loading spinner fo...

4 MIN READ
build-in-public · Apr 10, 2026
$ why your app needs an offline mo
# build-in-public
read-time: 4min

Why Your App Needs an Offline Mode (Even in 2026)

Why Your App Needs an Offline Mode (Even in 2026) If you're building a SaaS in 2026, you probably assume everyone has 5G. You assume everyone is always connecte...

4 MIN READ
growth-stories · Apr 10, 2026
14
growth
vs.
the default

Growth Metrics That Actually Matter for AI Products

Growth Metrics That Actually Matter for AI Products If you’re building an AI product, stop looking at your DAU (Daily Active Users) for a second. It might be ly...

4 MIN READ
ai-engineering · Apr 10, 2026
15

The Real Cost of "Free" AI APIs

Everybody's building with AI right now. OpenAI has a free tier. Anthropic gives you credits. Google hands out Gemini API access like candy at a conference. So y...

6 MIN READ
· Mar 30, 2026
16

Why I Chose React Native Over Flutter for BauGPT

Why I Chose React Native Over Flutter for BauGPT I get asked this question at every startup event. "Why React Native? Flutter is faster." Here's the honest answ...

5 MIN READ
ai-engineering · Mar 27, 2026
17

The 24/7 Autonomous Shipping System (And How I Built It)

I deployed 40+ TestFlight builds in a single week while I was at a team offsite in Munich. I barely touched my laptop. That's not an exaggeration — I was in mee...

5 MIN READ
industry-ai · Mar 20, 2026
18

German Construction Has No APIs. So We Built Our Own.

The German construction industry moves about 400 billion euros a year. You'd think there would be APIs for everything. Building permits, material specs, complia...

5 MIN READ
build-in-public · Mar 11, 2026
$ i built sso from scratch on baug
# build-in-public
read-time: 3min

I Built SSO From Scratch on BauGPT Mobile. Here's Why It Took 3 Days.

I spent 3 days on Sign in with Apple. Apple controls the device. The user is already logged in. Just press a button. Should've been an afternoon. The Setup Buil...

3 MIN READ
build-in-public · Mar 11, 2026
$ how i stopped bot spam without r
# build-in-public
read-time: 4min

How I Stopped Bot Spam Without Requiring Login

Every indie app gets hammered by bots eventually. Sond — the trip planning app — hit this around month 2. Suddenly 40% of new accounts were fake. They'd load th...

4 MIN READ
build-in-public · Mar 11, 2026
$ how a whatsapp bot brought 1000
# build-in-public
read-time: 4min

How a WhatsApp Bot Brought 1000 Test Users to Sond in 3 Weeks

Everyone says the same thing about indie launches: "Get on Twitter. Product Hunt will make or break you. Hacker News is where developers hang out." All true. Al...

4 MIN READ
thought-leadership · Mar 4, 2026
22

Why AI Doesn't Work for Most Startups (And How to Fix It)

"We added AI to our product!" crickets I see this pattern everywhere. Startup adds ChatGPT API. Slaps "AI-powered" on the landing page. Waits for users to care....

5 MIN READ
case-study · Mar 3, 2026
Case study
HEADLINE STAT

How We Solved the €500M Language Barrier Problem in German Construction

4 MIN READ
thought-leadership · Feb 19, 2026
24

What Is an AI Growth Engineer? (And Why You Need One)

I get asked this question a lot: "What exactly is an AI Growth Engineer?" Fair question. The role didn't exist 18 months ago. Here's what it actually means — an...

4 MIN READ
— THE NEWSLETTER

One note a week.
No fluff, just what works.

AI engineering, growth hacks, and messy lessons from shipping BauGPT. Unsubscribe anytime. I'll even miss you.

FIELD NOTES · NEXT ISSUE DROPS MONDAY
↳ No spam. One note weekly.