Authentication

Secure your LemonData API requests with API keys

API Keys

All LemonData API requests require an API key.

For OpenAI-compatible endpoints, send it as:

Authorization: Bearer sk-your-api-key

For Anthropic-compatible /v1/messages requests, you can also use:

x-api-key: sk-your-api-key

Management Tokens

Management API endpoints use a separate token type:

Authorization: Bearer mt-your-management-token

Use management tokens only with /v1/management/* endpoints. They are created from the Settings page in your Dashboard and are shown in full only once when generated or rotated.

Management tokens cannot be used for model inference, and standard sk-... API keys cannot be used for the Management API.

Getting Your API Key

1. Log in to your LemonData Dashboard
2. Open API Keys
3. Create a new key
4. Give it a descriptive name
5. Copy it immediately because it is shown only once

• Never expose API keys in client-side code
• Never commit API keys to version control
• Use environment variables or a secret manager
• Rotate keys periodically
• Delete unused keys

Using API Keys

cURL

curl https://api.lemondata.cc/v1/responses \
  -H "Authorization: Bearer $LEMONDATA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.4",
    "input": "Hello!"
  }'

API Key Features

Usage Limits

You can set a usage limit on each API key:

Setting	Description
No Limit	Key uses your account balance without restrictions
Fixed Limit	Key stops working after reaching the specified amount

Key Prefix

All LemonData API keys start with sk-.

Anthropic Compatibility

For the /v1/messages endpoint, the Anthropic-style header works as expected:

curl https://api.lemondata.cc/v1/messages \
  -H "x-api-key: sk-your-api-key" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Use Authorization: Bearer ... for OpenAI-compatible endpoints such as /v1/responses, /v1/chat/completions, /v1/models, and most other LemonData routes.

Error Responses

Status Code	Type	Code	Description
401	invalid_request_error	invalid_api_key	Missing or invalid API key
401	invalid_request_error	expired_api_key	API key has been revoked
402	insufficient_quota	insufficient_quota	Account balance is insufficient
402	insufficient_quota	quota_exceeded	API key usage limit reached

Example:

{
  "error": {
    "message": "Invalid API key provided",
    "type": "invalid_api_key",
    "code": "invalid_api_key"
  }
}