Balian Blog · September 28, 2026 · 4 min read

What Is an OpenAI-Compatible API — and Why Should You Care?

If you've read AI provider documentation, you've surely seen the term "OpenAI-compatible" or "OpenAI format". Simply put: OpenAI's API request/response format (the /v1/chat/completions endpoint) has become the industry's de-facto standard. Almost every provider — from DeepSeek to local gateways — uses the exact same format, differing only in base URL and API key.

Anatomy of the OpenAI Format

A request consists of just a few key elements:

POST /v1/chat/completions
Authorization: Bearer ***

{
  "model": "model-name",
  "messages": [
    {"role": "user", "content": "Hello, what is an AI API?"}
  ],
  "stream": false
}

The response always has the choices[0].message.content structure plus a usage object with token counts — that's what powers per-token billing.

Why Did This Become the Standard?

OpenAI arrived first and became the reference point. The entire ecosystem's tooling — official SDKs (Python/Node), LibreChat, Cursor, Discord/Telegram bot frameworks — was built against this format. A new provider that uses the same format instantly works with all of those tools, no extra adapter needed. The network effect is simply too strong to fight, which is why "compatible" is now a mandatory feature.

The Practical Payoff: Zero Vendor Lock-in

Because the format is identical, switching providers = changing two constants:

What changes	Example
`base_url`	`https://ai.balianapp.web.id/v1`
`api_key`	`balian-sk-...`

Swap models freely based on task and budget — light work on balian/mini (Rp 3,000 / ≈ $0.18 per 1M tokens), heavy coding on balian/deepseek-v4. All through a single integration. (USD figures are rough equivalents at Rp 16,500/USD.)

Try It Yourself in 2 Minutes

curl https://ai.balianapp.web.id/v1/chat/completions \
  -H "Authorization: Bearer ***" \
  -H "Content-Type: application/json" \
  -d '{"model":"balian/mini","messages":[{"role":"user","content":"hello!"}]}'

Try the API Now — Start from Rp 5,000 via QRIS →

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