Chat (original contract)

ApiLux's first public endpoint, with a leaner response. Kept permanently for existing integrations — new projects should use /chat/completions.

ImplementedAvailability depends on the selected model being enabled and priced in ApiLux.

Request

POST/chat

Requires the Authorization: Bearer apl_... header

Field	Type	Description
`model`required	string	Public model ID.
`messages`required	Message[]	Array of `{ role, content }`.

Response

Field	Type	Description
`reply`required	string	The generated content.
`tokensUsed`required	integer	Total tokens used.
`creditCharged`required	integer	Credits charged.
`balanceAfter`required	integer	Balance after the charge.

Billing

Same as /chat/completions.

Examples

cURL

curl https://apilux.net/api/v1/chat \
  -H "Authorization: Bearer apl_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "MODEL_ID",
    "messages": [{ "role": "user", "content": "Xin chào" }]
  }'

Errors

HTTP	Code	Meaning
400	`invalid_request`	Invalid body (missing field, wrong type, value out of range).
401	`auth_missing_or_malformed`	Missing `Authorization` header, or it is not in the `Bearer apl_...` form.
401	`auth_invalid`	The API key does not exist.
401	`auth_revoked`	The API key has been revoked.
401	`auth_expired`	The API key has expired.
400	`unknown_model`	The model does not exist on ApiLux.
400	`capability_not_supported`	The model exists but cannot be used on this endpoint (e.g. a text model on an image endpoint).
503	`pricing_not_configured`	The model is implemented but has no price configured on ApiLux yet. This is our state, not a client error.
503	`model_disabled`	The model is currently disabled.
503	`model_temporarily_unavailable`	The model is enabled and priced, but the upstream provider is not currently serving it. This is temporary and can clear on its own — the model reappears in `GET /v1/models` once the provider serves it again. You are not charged and no provider call is made.
402	`insufficient_balance`	Wallet balance is not enough for this request.
429	`api_key_limit_exceeded`	This API key hit a limit you configured yourself. The wallet still has funds — only this key is capped until the window resets. The response carries `limit_type` (`spending` \| `requests` \| `tokens`) and `period` (`daily` \| `monthly` \| `lifetime`). Token limits on text endpoints are measured from actual usage, so the total can exceed the limit by at most one request.
503	`api_key_quota_reconciliation_required`	An earlier text request on this same key has not been reconciled yet. The usual cause: the provider returned a successful result without token usage, so the token limit for that window can no longer be trusted and ApiLux stops rather than let the limit be exceeded silently. Retrying will not help until that is done — contact support. You are not charged for the blocked request, no provider call is made, and image/video endpoints are unaffected.
502	`upstream_error`	The model provider failed. You are not charged.
504	`upstream_timeout`	The provider did not respond in time. You are not charged.
429	`upstream_rate_limited`	Rate limited. Retry after a few seconds.

Notes

On this endpoint a disabled model returns unknown_model (400) rather than model_disabled (503) — the original behaviour is preserved deliberately.