Best API for Claude Code (2026) — subscription, Anthropic key, or a compatible gateway

Claude Code calls Anthropic's Messages API, and it reads two environment variables to decide where — ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN. That makes the question answerable in one sentence: anything that implements the Messages API can power Claude Code, which leaves three real options — a Claude subscription, an Anthropic API key, or a Messages-compatible gateway. Which one is best is not a feature question, it is a billing-shape question, and the honest answer is that a subscription wins for most individual daily users. This page is the decision, with the case for each.

Bias declared: Kunavo is one of the gateways in option three, and it is not the right answer for everybody — the section on when to stay on a subscription is not a courtesy, it is the recommendation for a large share of readers.

The three sources, and what each is for

The subscription-versus-API argument, stated properly

The loudest claim in this space is that a subscription is many times cheaper than the API — one of the pages ranking on this search puts it at 36×. That number is arithmetically fine and rests on an assumption its sources rarely state: it compares a subscription used to saturation against the token spend of the same workload. Under that assumption a flat fee obviously wins, and for a developer who codes most working days and regularly hits the window limit, it genuinely does. Anthropic's own plan pricing is the input to that calculation.

The assumption breaks in four ordinary situations, and then per-token billing is not merely competitive, it is the only thing that works:

• Bursty use. Two heavy weeks and a quiet month is common, and a flat fee does not scale to zero.
• Unattended runs. CI jobs, scheduled agents and scripted pipelines need a key, not an interactive plan session.
• Window exhaustion. When a plan's usage window is spent, work stops until it resets — inside the same plan there is no way to buy through it. The Claude Code cost page works the comparison through with current numbers.
• Team and per-project accounting. Separate keys with separate spend records are a per-token concept; a personal plan is not.

Useful in practice: these are not exclusive. Claude Code switches on two environment variables, so the common arrangement is a subscription for daily interactive work and a key for everything that happens when the window is spent or nobody is at the keyboard.

What actually has to work for Claude Code

Claude Code exercises more of the Messages API than a chat client does, so "OpenAI-compatible" is not the specification to check against. Four requirements decide whether a source works:

• /v1/messages, natively. Claude Code speaks Anthropic's Messages API, not the OpenAI chat-completions shape. An endpoint that offers only OpenAI compatibility needs a translation layer in front of it — which is what Claude Code Router exists to do.
• Streaming. Every response streams; a source that only supports buffered replies fails immediately.
• Prompt caching. This is the one that decides the bill. Claude Code re-sends a large system prompt and file context on every turn, so uncached input dominates the invoice — cached input is priced far below fresh input, and a source that does not support caching can cost several times more for identical work.
• The model IDs and context length you intend to use. Check the specific slugs, not the family name.

Option 3 in detail: pointing Claude Code at a gateway

A Messages-compatible gateway bills per token like the Anthropic API, with two differences that may or may not matter to you: the unit price can sit below Anthropic's list, and one key reaches models from more than one vendor. Kunavo implements /v1/messages with streaming and prompt caching, and lists Claude Sonnet 5 at $2.00 / $10.00 per 1M tokens against Anthropic's $2.00 / $10.00 — at list on this model today. Setup is the two variables:

# Claude Code reads these two variables. Set them and it bills
# per token against a key; unset them and it goes back to your plan.
# Note the base URL is the origin — no /v1 suffix.
export ANTHROPIC_BASE_URL=https://api.kunavo.com
export ANTHROPIC_AUTH_TOKEN=sk-kn-...

claude

# Back to the subscription:
# unset ANTHROPIC_BASE_URL ANTHROPIC_AUTH_TOKEN

The full setup, including the model-override variables and how to verify the connection, is on the Claude Code integration page. If you want to keep a subscription and switch to a key only when the window runs out, cc-switch manages the toggle.

When to stay on the subscription

If you use Claude Code interactively most working days, one session at a time, and you regularly reach the usage window, a plan is the cheaper answer and no gateway will beat it — the flat fee is doing real work for you. Switch, or add a key alongside, when the pattern stops matching: unattended runs, bursty months, more than one concurrent session, or per-project spend records. That is the whole decision, and for a large share of readers it ends here.

What the other results on this search are about

Worth naming, because the phrase is ambiguous and most pages ranking for it answer a different question. "Best AI clients for the Claude API" means chat front-ends — a different decision, covered by client integrations. "Best APIs to use with Claude Code" usually means data and integration services you let the agent call — MCP servers and SaaS connectors, not the model source. "Claude Code alternatives" means replacing the tool itself, which is a comparison of coding agents. If you arrived looking for one of those three, they are the pages to read instead.

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