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API Keys Guide
How to get API keys for Claude, OpenAI, and Gemini, and what they cost.
Projelli is a "bring your own key" (BYOK) tool. You sign up for an account directly with one or more AI providers, get an API key, and paste it into Projelli. This means:
- Your data stays private. AI requests go from your computer directly to the provider, Projelli is never in the loop.
- You pay the provider directly. Projelli doesn't mark up AI usage. You pay whatever the provider charges, no middleman.
- You control your usage. Set spending limits at the provider level. Switch providers or models any time.
You only need ONE provider to use Projelli. Most people start with Claude. You can add others later.
Where keys are stored: Projelli stores your API keys in your operating system's secure keychain, Keychain on Mac, Credential Manager on Windows, Secret Service on Linux. They're never written to a plain file, never logged, never sent anywhere except directly to the provider when you make a request. If you uninstall Projelli, your keys are removed from the keychain along with the app.
Anthropic (Claude)
Recommended for: long-form writing, document drafting, following complex instructions
- Go to console.anthropic.com and sign up (free)
- Add a payment method (you'll be billed only for actual usage)
- Click API Keys in the sidebar
- Click Create Key, give it a name like "Projelli", and copy the key (it starts with
sk-ant-)
- In Projelli, go to Settings → API Keys → Anthropic, paste the key, and click Save
Cost: Claude Sonnet (the default model) costs about $3 per million input tokens and $15 per million output tokens. A typical New Business Kickoff workflow run costs around $0.05-$0.20. Heavy daily use is usually $5-$15/month.
Free credits: Anthropic gives new accounts $5 in free credits. That's enough for ~50 workflow runs.
OpenAI (ChatGPT / GPT-4)
Recommended for: structured data extraction, JSON output, image-related tasks
- Go to platform.openai.com and sign up (free)
- Add a payment method
- Click API Keys in the sidebar (or go to platform.openai.com/api-keys)
- Click Create new secret key, give it a name like "Projelli", copy the key (it starts with
sk-)
- In Projelli, go to Settings → API Keys → OpenAI, paste the key, and click Save
Cost: GPT-4o costs about $2.50 per million input tokens and $10 per million output tokens. Comparable to Claude Sonnet for typical workflows. GPT-4o-mini is much cheaper (~$0.15 / $0.60) and fine for less demanding tasks.
Note: An OpenAI API account is separate from a ChatGPT Plus subscription. If you pay $20/mo for ChatGPT Plus, that does NOT give you API access, you need to set up billing separately on platform.openai.com.
Google AI (Gemini)
Recommended for: very long context windows, free tier for hobby use
- Go to aistudio.google.com/app/apikey (sign in with a Google account)
- Click Create API key
- Copy the key
- In Projelli, go to Settings → API Keys → Google, paste the key, and click Save
Cost: Gemini 2.0 Flash has a generous free tier (up to 15 requests/minute and 1500 requests/day at no charge). Beyond that, paid usage is roughly $0.075 per million input tokens, the cheapest of the three. Worth using as a "draft" model and switching to Claude or GPT for the final pass.
How to choose
| If you want… |
Use… |
| Best writing quality, long-form output |
Claude (Sonnet or Opus) |
| Reliable structured output, JSON, code |
GPT-4o |
| Cheapest, free tier for low-volume use |
Gemini Flash |
| Multiple perspectives on the same prompt |
All three (Projelli supports multi-model comparison) |
Setting spending limits
All three providers let you set hard spending caps on your account. We strongly recommend setting one, usage-based AI billing can get expensive fast if something runs in a loop.
- Anthropic: Console → Plans & Billing → Cost limits
- OpenAI: platform.openai.com → Settings → Limits → Set monthly budget
- Google: Google Cloud Console → Billing → Budgets & alerts
A reasonable starting limit is $10/month per provider. Adjust up if you find yourself hitting it often.
What if my key gets compromised?
If you suspect your API key has been exposed (committed to a public git repo, shared in a screenshot, etc.):
- Go to your provider's API keys page
- Revoke the compromised key
- Create a new key
- Update Projelli with the new key (Settings → API Keys)
Compromised keys can be used to run up charges on your account, so revoke immediately if there's any doubt.
Why bring your own key instead of paying Projelli?
This is a deliberate design choice. By having you bring your own key:
- Your privacy is real. If we routed AI calls through our servers, we'd be a man-in-the-middle who could (in theory) read your prompts. We don't want to be in that position. With BYOK, the cryptography goes user → provider, end of story.
- No usage caps from us. You're limited only by your own provider account.
- You don't pay markup. The provider's prices are what you pay.
- You can use models we haven't enabled yet. When Anthropic releases a new Claude model, you can use it as soon as it's in their API, no waiting for us to update.
The downside is the small setup hurdle. Once it's done, it's done, you don't think about it again.