Authentication - NinjaChat Developers

Authorization: Bearer nj_sk_YOUR_API_KEY

Get a key

Create one at Developers → Connections → Apps. Keys start with nj_sk_ and are shown once — copy immediately. Browsing and estimates are free. Paid calls draw from your Developer Balance — top up at Developers → Billing, or verify your phone on your first paid action to unlock a $0.50 starter balance.

Use it

curl -X POST https://www.ninjachat.ai/api/v1/chat \
  -H "Authorization: Bearer $NINJACHAT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-5", "messages": [{"role": "user", "content": "Hello"}]}'

import os, requests

r = requests.post("https://www.ninjachat.ai/api/v1/chat",
    headers={"Authorization": f"Bearer {os.environ['NINJACHAT_API_KEY']}"},
    json={"model": "gpt-5", "messages": [{"role": "user", "content": "Hello"}]}
)

const r = await fetch("https://www.ninjachat.ai/api/v1/chat", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.NINJACHAT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "gpt-5",
    messages: [{ role: "user", content: "Hello" }],
  }),
});

Keep it secret

Environment variables, never hardcoded:

export NINJACHAT_API_KEY="nj_sk_YOUR_API_KEY"   # or a .env file in .gitignore

And never in frontend code — CORS is open on /api/v1/*, but a key in the browser is a key stolen. Proxy through your backend:

@app.post("/api/chat")
def proxy(req):
    return requests.post("https://www.ninjachat.ai/api/v1/chat",
        headers=HEADERS,  # server-side only
        json={"model": "gpt-5", "messages": req.json["messages"]}
    ).json()

Key management

Up to 5 active keys per account — use separate keys for dev / staging / prod
Revoke instantly from Developers → Connections → Apps; revoked keys stop immediately
The same key works for the MCP server — agents and code share one balance

Auth errors

Status	Error	Fix
401	`missing_api_key`	Add the `Authorization: Bearer nj_sk_...` header
401	`invalid_api_key`	Key is malformed or revoked — create a new one