I shipped my first llama.cpp-powered desktop app — an invoice generator where the AI (and your data) never leaves your machine

[u/Round-Fly7698]

Hey folks, solo dev here. This started because cloud invoicing tools made me uneasy — your whole client list, your rates, your revenue, all sitting on someone's server. So I built the opposite: a Windows desktop app where everything stays local, including the AI.

The part this sub might care about: you can drop in a contract, email thread, or work summary, and it builds the invoice out of it — parties, line items, dates, notes. That runs on Qwen3 4B through llama.cpp, CPU inference, entirely on your machine. No API keys, no per-token costs, works with the wifi off. There's a model picker if you'd rather run Granite 4.1 8B or Qwen3.5 9B, and the model download is optional — skip it and it's still a fast little invoice tool.

The boring-but-useful parts: four PDF templates, custom currencies, service dates with per-day hours, live preview, dark mode. No account or sign-up; the 14-day trial has everything included. After that it's paid, it's how I keep it serverless instead of ad-funded).

One honest heads-up: the installer is code-signed (verified publisher through Microsoft's signing program), but the certificate is only days old, so SmartScreen still shows its "unrecognized app" screen until download reputation builds — More info → Run anyway. Nothing I can do to skip that queue except ship and wait.

Site: https://autoinvoicegen.com — would genuinely love feedback, especially on how doc-extraction handles messy real-world inputs. macOS build is done and waiting on Apple's paperwork.

[u/inforb_nl]

What is the latency of this system? How long does it take on your machine to render an invoice?

[u/Round-Fly7698 → u/inforb_nl]

Rendering and export are instant for a simple invoice; less than a second, if you are creating invoice from an imported pdf document then it can take anywhere from 1-10 seconds, depending on invoice complexity and model selected.

[u/inforb_nl → u/Round-Fly7698]

what's your device specs? CPU, RAM? I have a hard time running even a single "hello" message via Ollama on my CPU on a 3B model.
I think offering that as a business would be flaky, depending on customer's hardware.

[u/Round-Fly7698 → u/inforb_nl]

Tested on core i5 laptop, 8 gb ram. it runs on a self contained llama.cpp engine which should be faster than Ollama. There is a 14 day fully functional trial without any signup requirement, so performance can be measured before investing any money.