API reference

Base URLs

Pick the one that matches your SDK. Both share one key and one balance.

Authentication

Send your API key in a header on every request. Create keys on the API Keys page of the console; a key is shown only once, when you create it.

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

The Anthropic endpoints take an x-api-key header and also accept Authorization: Bearer.

Manage API keys →

Endpoints

All paths are under https://nezhagate.com. Synchronous endpoints return the result; image and video endpoints return a job id.

Async jobs (images and video)

Image and video calls return HTTP 202 with a job id at once; the work runs in the background. Poll with the id, or have the result pushed to you by webhook.

curl https://nezhagate.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "nano-banana-2", "prompt": "a lighthouse at dawn, watercolor", "size": "16:9"}'

# HTTP 202
{"id": "img_3f9a...c2", "object": "image.generation.job", "status": "queued", "model": "nano-banana-2"}

curl https://nezhagate.com/v1/images/jobs/img_3f9a...c2 -H "Authorization: Bearer YOUR_API_KEY"

{
  "id": "img_3f9a...c2",
  "object": "image.generation.job",
  "status": "succeeded",
  "created": 1791199400,
  "model": "nano-banana-2",
  "data": [{"url": "https://img.nezhagate.com/i/9f86d081a8....png"}],
  "usage": {"images": 1, "resolution": "1K", "model": "nano-banana-2"}
}

• Poll images every 2–3 seconds and video every 5–10 seconds. Polling is free.
• data[0].url is a link on our media host, kept for 60 days and then deleted; download anything you need to keep.
• Add callback_url when you submit, and the same result the poll returns is pushed to that URL when the job ends. Webhook docs →

List models

Returns every model ID on sale, in the OpenAI format. Retired models are not listed; a coming-soon model is listed but answers 400 model_coming_soon until it opens.

curl https://nezhagate.com/v1/models -H "Authorization: Bearer YOUR_API_KEY"

{"object": "list", "data": [{"id": "gpt-5.5", "object": "model", "owned_by": "..."}, {"id": "claude-sonnet-5", "object": "model", "owned_by": "..."}]}

Balance & usage

Any API key can read the account's balance and spend. No console login needed.

curl https://nezhagate.com/v1/usage -H "Authorization: Bearer YOUR_API_KEY"

{
  "object": "usage",
  "balance": {"usd": 12.5, "credits": 2500},
  "total": {"cost_usd": 37.5, "requests": 1840, "billed_requests": 1822, "failed_requests": 18},
  "today": {"cost_usd": 1.2, "requests": 64, "billed_requests": 63, "failed_requests": 1},
  "by_model": [
    {"model": "gpt-5.5", "cost_usd": 20.1, "requests": 900, "billed_requests": 896, "failed_requests": 4,
     "prompt_tokens": 1520000, "completion_tokens": 410000, "image_count": 0}
  ]
}

balance.usd is the balance in US dollars and balance.credits the same in credits (1 USD = 200 credits).

For tools that already know how to check an OpenAI balance, use the OpenAI-style endpoint; the balance is total_available.

curl https://nezhagate.com/v1/dashboard/billing/credit_grants -H "Authorization: Bearer YOUR_API_KEY"

Error format

Every error has the same shape. code is a stable, machine-readable identifier: branch on code, never on the message text.

{
  "error": {
    "message": "Model not enabled: gpt-9",
    "type": "invalid_request_error",
    "code": "model_not_found",
    "param": "model"
  }
}

Full list of error codes →

Rate limits & retries

• Accounts have no default request-rate limit. In the console you can give each key its own requests-per-minute cap, daily budget, total spend limit, model allowlist and IP allowlist.
• On a 429, wait as long as the Retry-After header says, then retry. For 502, 503 and timeouts, retry with exponential backoff (for example 1, 2, then 4 seconds).
• Failed requests are never billed. If a stream breaks off midway, you pay only for what was returned.
• For sustained high concurrency, tell us ahead of time and we will add capacity for your volume.

SDKs & examples

No special SDK needed: the official OpenAI and Anthropic SDKs work once you change base_url.

from openai import OpenAI

client = OpenAI(base_url="https://nezhagate.com/v1", api_key="YOUR_API_KEY")
resp = client.chat.completions.create(
    model="gpt-5.5",
    messages=[{"role": "user", "content": "Hello"}],
    stream=True,
)
for chunk in resp:
    print(chunk.choices[0].delta.content or "", end="")

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://nezhagate.com/v1", apiKey: "YOUR_API_KEY" });
const resp = await client.chat.completions.create({
  model: "gpt-5.5",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(resp.choices[0].message.content);

import anthropic

client = anthropic.Anthropic(base_url="https://nezhagate.com/anthropic", api_key="YOUR_API_KEY")
msg = client.messages.create(
    model="claude-sonnet-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello"}],
)
print(msg.content[0].text)

More runnable examples (Python, Node.js, curl, including the async image and video flow): github.com/gaoorange/nezhagate-api-examples

Docs for each model

Every model has its own page: allowed parameter values, example code, the response format and how it is billed.

Chat models

• GPT-5.6 Sol
• GPT-5.6 Terra
• GPT-5.6 Luna
• GPT-5.5
• GPT-6 Astra
• GPT-6.1 Sol
• GPT-6 Sol
• GPT-6 Luna
• Claude Sonnet 4.6
• Claude Opus 5
• Claude Fable 5
• Claude Sonnet 5
• Claude Opus 5.5
• Claude Sonnet 5.5
• Gemini 3.1 Pro
• Gemini 3.8 Flash
• Gemini 3.7 Flash
• Gemini 3.6 Flash
• Gemini 3.6 Flash High
• Gemini 3.6 Flash Low
• Gemini 3.6 Flash Tiered
• Gemini 3 Flash
• Gemini 2.5 Flash
• DeepSeek V4.1 Flash
• DeepSeek V4 Flash 0731
• GLM-5.3
• GLM-5.3 Flash
• Kimi K3
• Qwen3.7 Max
• Qwen3.8 Max
• Qwen3.8 Max 0902
• Qwen3.8 Flash
• Doubao Seed 2.1 Pro
• Doubao Seed 2.1 Turbo
• Grok 4.7

Image models

• GPT Image 2
• GPT Image 2.5 Flare
• GPT Image 2.5 Sunburst
• Nano Banana 2
• Nano Banana Pro
• Grok Imagine Image
• Grok Imagine Image Quality

Video models

• Veo 3.1
• Gemini Omni Flash
• Seedance 2.5
• Seedance 2.0
• Seedance 2.0 Fast
• Seedance 2.0 · Clip
• Seedance 2.5 · 30s
• Wan 3.0
• Wan 3.0 Prime
• MiniMax H3
• Grok Imagine Video 1.5