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Lithtrix uses API keys for authentication. You get a key by calling POST /v1/register — there is no dashboard, email confirmation, or OAuth flow. Once you have a key, pass it as a Bearer token in the Authorization header of every authenticated request. This page explains how to get the key, use it, rotate it, and understand your usage limits.

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Get your API key

Call POST /v1/register with an agent_name and an owner_identifier. The response includes a one-time api_key field. 
curl -X POST https://lithtrix.ai/v1/register \
  -H "Content-Type: application/json" \
  -d '{"agent_name":"my-agent","owner_identifier":"you@example.com"}'
Example response: 
{
  "api_key": "ltx_a3f9b2c1d5e7...",
  "agent_id": "550e8400-e29b-41d4-a716-446655440000",
  "message": "Store this key securely. It cannot be retrieved again."
}
The api_key value is returned only once and cannot be retrieved again. Store it in a secure location — an environment variable, a secrets manager, or encrypted configuration — before you make any other request. If you lose the key, you must rotate it to get a new one.

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Use your API key

Pass your key in the Authorization header using the Bearer scheme on every authenticated request: 
Authorization: Bearer ltx_your_api_key
For example, to search the web: 
curl "https://lithtrix.ai/v1/search?q=renewable+energy+policy" \
  -H "Authorization: Bearer ltx_your_api_key"
Or in Python: 
import requests

resp = requests.get(
    "https://lithtrix.ai/v1/search",
    params={"q": "renewable energy policy"},
    headers={"Authorization": "Bearer ltx_your_api_key"},
    timeout=15,
)
resp.raise_for_status()
All ltx_ keys follow the same format. Keys that begin with anything else are invalid.

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Rotate your key

If your key is compromised or you want to issue a new one, call POST /v1/keys/rotate with your current key: 
curl -X POST https://lithtrix.ai/v1/keys/rotate \
  -H "Authorization: Bearer ltx_your_current_key"
The response contains your new key. The old key is invalidated immediately upon rotation.
Any in-flight requests using the old key will fail after rotation. Update all services and agents that hold the key before rotating, or accept a brief period of authentication errors during the cutover.

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Free tier limits

New agents start on the free tier, which includes 300 lifetime calls. This quota never resets — once you use 300 calls, searches will return an error until you upgrade. Check your current usage and tier at any time: 
curl https://lithtrix.ai/v1/billing \
  -H "Authorization: Bearer ltx_your_api_key"
Example response: 
{
  "tier": "free",
  "calls_total": 47,
  "call_limit": 300,
  "calls_remaining": 253,
  "over_limit": false
}
To upgrade to the Pro tier (unlimited calls, 600 requests/min), follow the billing upgrade flow:
  1. Call GET /v1/billing/config to retrieve the Stripe configuration.
  2. Create a Stripe PaymentMethod using the config.
  3. Call POST /v1/billing/setup with the PaymentMethod ID to activate Pro.
See the Billing API reference for the full upgrade flow.