Zukko Blog
Guides to Claude Code, Cursor, Codex and the Claude and GPT APIs: setup, token savings and troubleshooting.
Migrating a project from the official API to a gateway
2 min · · migration
Moving to a compatible gateway is two lines of configuration and an hour of verification. Here is exactly what changes.
Why your token count is higher than your prompt
2 min · · tokens
A five-word question shows up as thousands of tokens in your usage. That is not a billing bug — here is the breakdown.
Cursor does not see your models after changing the base URL
2 min · · cursor
The key is in, the URL is replaced, and the model list is empty or verification fails. Four causes by frequency.
Your API key leaked — a step-by-step response
2 min · · security
A leaked key means a growing bill. The first steps take a minute, and their order matters more than speed.
Common API connection errors and how to read them
3 min · · errors
Connecting usually takes two minutes; when it does not, the cause is almost always one of four things. How to read the server's answer.
Which model to choose when they all share one key
3 min · · models
When every model sits behind one key, the choice stops being technical and becomes economic. How to pick without overpaying.
Base URL with or without /v1 — which client needs what
2 min · · setup
The same gateway needs different base URLs in different clients. Getting the suffix wrong yields a 404 with no useful explanation.
Do you need a VPN for the Claude and GPT APIs
2 min · · access
A VPN solves the wrong problem. What is blocked is the payment, not the address — and your exit IP does not change that.
Paying for Cursor from Russia: connect your own API key
3 min · · cursor
Cursor's subscription needs a foreign card, but the editor can talk to any OpenAI-compatible API with your own key.
How to pay for the Claude API from Russia in 2026
3 min · · payments
Anthropic does not accept cards issued by Russian banks. Three routes that work, with the honest caveats for each.
What the Claude API really costs
3 min · · pricing
A rate per million tokens means nothing until you know your own workload. Here is how to actually estimate it.
Paying for AI models with crypto: how it actually works
3 min · · payments
Neither Anthropic nor OpenAI accepts crypto, so the real question is about intermediaries. What to watch for, and what crypto does not buy you.
Claude Code from scratch: install and configure with your own key
3 min · · claude-code
Installing Claude Code and configuring it to run on your own API key, step by step, including the mistakes almost everyone makes.
Codex without a ChatGPT subscription: pointing it at another API
3 min · · codex
Codex takes its provider from a config file, so you can point it anywhere compatible. Here is the exact config and what each field does.
Hitting Claude usage limits: what to do
3 min · · limits
The quota runs out mid-week and money cannot buy your way past it. Why the cap exists and what the alternatives actually cost.
Claude Code without a subscription: connecting via API key
3 min · · claude-code
Claude Code works with a plain API key, not only with a subscription. Then you pay for the tokens you used, not for a month.