With AI becoming part of everyday coding for software engineers, I found myself spending more and more time building apps for myself and my family, working with private personal data on my own computer. But I kept running into the same chores: configuring AI providers, storing credentials, and figuring out how to deploy each app. Even a small change meant opening a terminal, switching to the project directory, starting a coding agent, then deploying again. AI had made writing code much faster, but the whole process still felt fiddly.
I wanted one place where I could build an app, use it right away, and change it without friction—with changes taking effect as I made them, no deployment needed. I wanted those apps to run on my own computer and keep their data there, so I could work with private information comfortably, without having to upload it to a third-party server just to run an app.
I wanted a shared set of AI providers and credentials I could manage once for all my apps. I also wanted to choose whichever providers I liked and make AI features and agents easy to add.
That’s why I built AppJuice. I’ve been working on it pretty actively over the past few months, and it’s now at around version 0.370. I’m still updating it regularly, and I’ve also built a dozen apps for it along the way.
Build, use, and tweak in one place
AppJuice is a local-first platform for building and running private AI apps on your computer. It provides the app runtime, so an app can run from the first line of code, with its own interface and persistent local data. There’s no separate deployment step before you can start using it.
When I want to change something, I can summon the builder agent in Tweak mode and ask for the change. It takes effect in the running app right away. That makes it easier to keep adjusting an app as I use it, rather than treating every small change as another trip back into a development project.
AI providers and capabilities, shared across apps
Instead of setting up AI providers separately for each app, I configure them once in AppJuice. The platform supports 50+ AI provider integrations, including OpenAI, Anthropic, Google, DeepSeek, and MiniMax, as well as local models through Ollama or LM Studio. I can choose the providers I prefer and select models for each capability.
Those capabilities include text generation, image understanding and generation, transcription, speech synthesis, music and video generation, and web search. Apps and agents can use them through the platform’s shared APIs and tools, without each app having to handle provider configuration and credentials on its own.
Agents inside apps
I also wanted an app to have its own agents, tools, skills, and context. AppJuice provides a complete Agent SDK, along with ready-to-use UI components for conversations, model selection, approvals, attachments, and generated artifacts.
For workflows that need multiple agents, it supports code-first multi-agent orchestration: I can define the flow and how the agents coordinate directly in code.
Keep it local, or make it available elsewhere
Apps run locally by default. When I use a cloud AI provider, the context needed for that request is sent to the provider I selected. File and tool access is governed by platform permissions and my approvals.
For access from my other devices, I can use Tailscale to reach apps running on my computer. And when I do want a public website, I can ask the builder agent to deploy a static site or an app with a backend in one sentence, with a cloud host configured.
The Juicery: a marketplace for apps
The Juicery is AppJuice’s app marketplace. Anyone can upload an app they’ve built for others to discover, install, and remix. It’s still under construction, and I plan to add support for selling apps in the future.
When an app is uploaded, it goes through multiple stages of AI scanning. These checks are designed to make sure the shared package contains the app’s code, without personal data, provider credentials, or malicious code. The idea is to share the app itself, while keeping the creator’s private runtime data separate.
AppJuice is available in Preview for macOS 13.5+, on Apple Silicon and Intel. If this sounds like something you’d find useful too, you can try AppJuice or take a look at the user guide.