Build Apps with Your Own API Key

Most AI app builders charge $20 to $100 per month for subscriptions that bundle AI access with their platform. The actual AI costs behind those subscriptions are a fraction of what you pay. If you bring your own API key to a tool like Dyad, you skip the markup entirely and pay only for the tokens you use.

What cloud AI builders actually cost

Here is what the major platforms charge today:

• Lovable: $25/month for 100 credits. Heavy usage requires the $50+ tiers.
• Bolt.new: $20/month for 10 million tokens. Complex projects burn through this fast.
• Replit: $20-25/month base, but effort-based pricing means real-world costs often land between $100 and $300/month.
• v0: $20/month for premium. Free tier gives roughly $5 of tokens.

These platforms handle API access for you, which is convenient. But you are paying a premium for that convenience, and you are locked into whichever models and providers they support.

What AI tokens actually cost

When you bring your own API key, you pay the provider's published rate per token. Here are approximate costs for building a typical small web app (roughly 50 prompts over a few days):

A project that costs $0 to $6 in raw API usage would cost $20 to $100+ on a cloud platform subscription. That is where the 10x savings come from.

Google's Gemini API offers 500 free requests per day. For many projects, that is enough to build an entire app without spending anything on AI.

How to set up your API keys in Dyad

Dyad is an open-source desktop app that runs locally on Mac, Windows, and Linux. It supports multiple AI providers, and you can switch between them at any time.

Google Gemini (recommended for free usage)

1. Go to aistudio.google.com/apikey and create an API key.
2. Open Dyad, go to Settings, and find the AI Providers section.
3. Paste your key under Google Gemini.
4. Select a Gemini model from the model picker. Gemini 2.5 Flash is a good default.

Keep in mind that Google's free tier allows them to use your data for training. If that is a concern, add a billing plan to opt out.

OpenAI

1. Go to platform.openai.com and create an API key.
2. Add a payment method (most models require it, though GPT-4.1 mini has a limited free tier).
3. In Dyad, paste your key under OpenAI in settings.
4. Pick a model. GPT-4.1 mini gives strong results at low cost. GPT-4.1 is better for complex tasks.

Anthropic

1. Go to console.anthropic.com and create an API key.
2. Add a payment method (Anthropic has no free tier).
3. In Dyad, paste your key under Anthropic in settings.
4. Claude Sonnet 4 is a strong choice for coding tasks.

OpenRouter (access many models with one key)

1. Go to openrouter.ai and create an account.
2. Generate an API key.
3. In Dyad, paste your key under OpenRouter.
4. You now have access to dozens of models, including free ones like DeepSeek v3.

Local models (zero cost)

If you want to avoid API costs entirely, run models locally through Ollama or LM Studio. Install either tool, download a model, and Dyad will detect it automatically in the model picker under Local Models.

Trade-off: local models require decent hardware, and smaller models may produce less reliable output than cloud models.

Why model flexibility matters

With a subscription-based builder, you use whatever model the platform provides. If that model performs poorly on your task, you are stuck.

When you bring your own API key, you can switch models mid-project:

• Use Gemini 2.5 Flash for quick iterations during early prototyping (free).
• Switch to GPT-4.1 or Claude Sonnet 4 for tricky logic or debugging.
• Drop down to GPT-4.1 mini for simple UI changes to save money.
• Run a local model through Ollama for offline work or privacy-sensitive projects.

Dyad's Auto mode handles this automatically. It picks the most suitable available model based on your configured providers. You can also override it at any time.

The real cost of a typical project

Consider building a task management app with authentication, a database, and a polished UI. Across 3-5 days of active building, you might send 80-120 prompts.

On a cloud platform: You are paying at least $20/month. If you hit credit limits, you upgrade or wait. Over a few months of building, you spend $60-300.

With your own API key in Dyad: Using Gemini 2.5 Flash on the free tier, you pay $0. Mixing in some GPT-4.1 prompts for harder problems, maybe $2-5 total. Even using exclusively premium models like Claude Sonnet 4, the total stays under $10.

The math gets more favorable over time. Subscriptions cost the same whether you build one app or take a week off. API keys charge only for what you use.

What you get with Dyad beyond BYOK

Bringing your own API key is the cost story, but Dyad includes features you would expect from a full development environment:

• Version control built in. Every AI change is tracked. Undo and restore any previous state.
• GitHub integration. Push to repos, connect existing projects, work with branches.
• Supabase integration. Set up authentication, databases, and edge functions directly.
• MCP server support. Extend Dyad with external tools and services.
• Visual editing mode. Click elements in the preview to edit them visually.
• Ask mode. Plan and discuss your app with AI before generating code.
• Agent mode. The AI gathers context automatically and debugs its own errors. Free users get 5 agent messages per day.

The code Dyad generates is standard. It uses common frameworks and tools. You can open it in any editor, deploy it anywhere, and continue without Dyad if you choose.

When a subscription makes more sense

Bring your own API key is not the right fit for everyone.

If you do not want to manage API keys and billing across providers, a subscription simplifies that. If you need collaborative editing with multiple people in real time, cloud platforms handle that natively. If you prefer not to run a local development environment, browser-based builders remove that requirement.

Dyad Pro ($20/month) is also an option if you want included AI credits without managing keys, plus features like full Agent mode, Turbo Edits, and Smart Context.

Getting started

1. Download Dyad from dyad.sh. It runs on Mac, Windows, and Linux.
2. Set up at least one API key (Google Gemini is the fastest free option).
3. Create a new app and start building.

Your code stays on your machine. Your API keys stay in your local settings. You pick the model, you control the cost.