Cumbersome: AI LLM API Client

IMPORTANT: Requires your own API keys from OpenAI, Anthropic, OpenRouter, Google AI Studio, Z.ai, or Vercel AI Gateway, or your own OpenAI-compatible endpoint.

I built Cumbersome because consumer AI apps kept dumbing things down. Cumbersome is the manual transmission of AI apps: more complex, but with far greater control.

WHY I BUILT THIS

Consumer AI providers like ChatGPT and Claude route requests to cheaper models to keep their costs down. They charge monthly subscriptions whether you use them once or a thousand times. They hide the technical controls that let you tune how models respond. And they lock you into one provider.

I wanted an AI client that connects directly to AI provider APIs. I wanted to pick exactly which model I use and know I'm getting it. I wanted to compare different models on the same prompt. I wanted to pay per use instead of subscriptions. So I built it. This is the app I use every day to interact with AI, so I pay attention and try to get it right.

SUPPORTED PROVIDERS

Bring your API keys, or add your own OpenAI-compatible endpoint, for any of the following:

— ChatGPT / OpenAI

— Claude / Anthropic

— Gemini / Google AI Studio

— OpenRouter multi-provider

— Vercel AI Gateway multi-provider

— Z.ai

— OpenAI-compatible custom endpoints, including Ollama, Azure, LM Studio, Groq, Together, and self-hosted backends

WHAT YOU GET

— A free app.

— A versatile API client. One app, every major provider and model.

— Total control. Pick your model, tune the parameters, switch providers mid-conversation.

— Compare models head to head. Stream multiple chats in parallel and let an AI judge pick the best.

— Bring your own tools. Local browser use, reasoning, web search, image generation.

— Rich, editable conversations. Markdown, LaTeX, code blocks, attachments, edit and export anything.

— Private by design. iCloud sync across devices. Nothing saved to our servers.

— Native and accessible on iPhone, iPad, and Mac.

MAJOR FEATURES ADDED IN 2026

Highlights only. See What's New on the App Store for the latest.

2026-07-02: Chat appearance themes and reading fonts (Serif, Rounded, Mono).

2026-06-28: Folder-level system message presets.

2026-06-24: Prompt caching, with cache usage shown across providers.

2026-06-17: Reusable system message presets per conversation.

2026-06-16: Offload long system messages to iCloud Drive.

2026-06-15: Pause custom API parameters with a toggle.

2026-06-11: Compact a conversation to lower API costs.

2026-06-07: Run JavaScript and HTML directly from Cumbersome.

2026-06-04: Choose how OpenRouter parses PDFs and which search engine it uses.

2026-05-12: Configurable Quick Prompt shortcut and App Visibility on Mac.

2026-05-09: Conversation folders. Group, move, and organize chats.

2026-05-03: Collapsible sidebar sections, synced across devices.

2026-04-22: AI image generation with OpenAI and Gemini.

2026-04-18: Local browser tool use. AI can search and browse pages.

2026-04-11: Headless mode. The AI works the browser in the background.

2026-04-03: Searchable model picker for long model lists.

2026-03-15: Extended thinking and reasoning across providers.

2026-03-09: Auto-delete conversations after a set number of days.

2026-02-28: OpenAI-compatible custom providers (Ollama, Azure, LM Studio, Groq).

2026-02-25: Only Search When Requested. Keep web search off until you ask.

2026-02-24: Image paste, interactive attachment previews, and PDF thumbnails.

2026-02-21: Siri and Shortcuts integration.

2026-02-20: Vercel AI Gateway support, with model exclusion filters.

2026-02-06: Voice Control, Larger Text, and higher contrast.

2026-01-11: Major accessibility pass. VoiceOver, Dynamic Type, keyboard nav.

2026-01-06: OpenRouter multi-provider integration.

THE DEAL

The app is free. You pay providers directly for API access.

I'm Peter, an indie developer in Reno, Nevada, out among the high desert tumbleweed. No VC money. No growth hacking. Just a tool I wanted to exist.