> ## Documentation Index > Fetch the complete documentation index at: https://docs.helicone.ai/llms.txt > Use this file to discover all available pages before exploring further. # Chat Completions (Gateway) > Create chat completions via the AI Gateway This request schema applies when using the Helicone AI Gateway with pass‑through billing (credits). In BYOK mode, the standard OpenAI Chat Completions schema is allowed. The schema is defined based on fields that are stable across all provider-model mappings. [Learn more about pass‑through billing vs BYOK](/gateway/provider-routing). ```bash cURL theme={null} curl https://ai-gateway.helicone.ai/v1/chat/completions \ -H "Authorization: Bearer $HELICONE_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-4o-mini", "messages": [ { "role": "system", "content": "You are a helpful assistant." }, { "role": "user", "content": "Say hello in one sentence." } ] }' ``` ```typescript TypeScript theme={null} import OpenAI from "openai"; const client = new OpenAI({ baseURL: "https://ai-gateway.helicone.ai/v1", apiKey: process.env.HELICONE_API_KEY, }); const response = await client.chat.completions.create({ model: "gpt-4o-mini", messages: [ { role: "system", content: "You are a helpful assistant." }, { role: "user", content: "Say hello in one sentence." }, ], }); ``` ```python Python theme={null} import os from openai import OpenAI client = OpenAI( base_url="https://ai-gateway.helicone.ai/v1", api_key=os.environ.get("HELICONE_API_KEY"), ) response = client.chat.completions.create( model="gpt-4o-mini", messages=[ {"role": "system", "content": "You are a helpful assistant."}, {"role": "user", "content": "Say hello in one sentence."}, ], ) ``` ## OpenAPI ````yaml post /v1/chat/completions openapi: 3.0.0 info: title: Helicone AI Gateway API version: 1.0.0 description: OpenAPI spec derived from Zod schemas for AI Gateway. servers: - url: https://ai-gateway.helicone.ai security: [] paths: /v1/chat/completions: post: summary: Create Chat Completion requestBody: required: true content: application/json: schema: type: object properties: metadata: anyOf: - type: object additionalProperties: {} - type: string nullable: true enum: - null top_logprobs: nullable: true type: integer minimum: 0 maximum: 20 temperature: anyOf: - type: number - type: string nullable: true enum: - null top_p: anyOf: - type: number - type: string nullable: true enum: - null top_k: anyOf: - type: number - type: string nullable: true enum: - null user: type: string safety_identifier: type: string prompt_cache_key: type: string cache_control: type: object properties: type: type: string enum: - ephemeral ttl: type: string service_tier: anyOf: - type: string enum: - auto - default - flex - scale - priority - type: string nullable: true enum: - null messages: minItems: 1 type: array items: anyOf: - type: object properties: content: anyOf: - type: string - type: array items: type: object properties: type: type: string enum: - text text: type: string required: - type - text role: type: string enum: - developer name: type: string required: - content - role - type: object properties: content: anyOf: - type: string - type: array items: type: object properties: type: type: string enum: - text text: type: string required: - type - text role: type: string enum: - system name: type: string required: - content - role - type: object properties: content: anyOf: - type: string - type: array items: anyOf: - type: object properties: type: type: string enum: - text text: type: string required: - type - text - type: object properties: type: type: string enum: - image_url image_url: type: object properties: url: type: string format: uri detail: default: auto type: string enum: - auto - low - high required: - url required: - type - image_url - type: object properties: type: type: string enum: - document source: type: object properties: type: type: string enum: - text media_type: type: string data: type: string required: - type - media_type - data title: type: string citations: type: object properties: enabled: type: boolean required: - enabled required: - type - source role: type: string enum: - user name: type: string required: - content - role - type: object properties: content: anyOf: - anyOf: - type: string - type: array items: anyOf: - type: object properties: type: type: string enum: - text text: type: string required: - type - text - type: object properties: type: type: string enum: - refusal refusal: type: string required: - type - refusal - type: string nullable: true enum: - null refusal: anyOf: - type: string - type: string nullable: true enum: - null role: type: string enum: - assistant name: type: string audio: anyOf: - type: object properties: id: type: string required: - id - type: string nullable: true enum: - null tool_calls: type: array items: anyOf: - type: object properties: id: type: string type: type: string enum: - function function: type: object properties: name: type: string arguments: type: string required: - name - arguments required: - id - type - function - type: object properties: id: type: string type: type: string enum: - custom custom: type: object properties: name: type: string input: type: string required: - name - input required: - id - type - custom function_call: anyOf: - type: object properties: arguments: type: string name: type: string required: - arguments - name - type: string nullable: true enum: - null required: - role - type: object properties: role: type: string enum: - tool content: anyOf: - type: string - type: array items: type: object properties: type: type: string enum: - text text: type: string required: - type - text tool_call_id: type: string required: - role - content - tool_call_id - type: object properties: role: type: string enum: - function content: anyOf: - type: string - type: string nullable: true enum: - null name: type: string required: - role - content - name model: type: string modalities: anyOf: - type: array items: type: string enum: - text - type: string nullable: true enum: - null verbosity: anyOf: - type: string enum: - low - medium - high - type: string nullable: true enum: - null reasoning_effort: anyOf: - type: string enum: - minimal - low - medium - high - type: string nullable: true enum: - null reasoning_options: type: object properties: budget_tokens: type: integer minimum: -9007199254740991 maximum: 9007199254740991 required: - budget_tokens max_completion_tokens: nullable: true type: integer minimum: -9007199254740991 maximum: 9007199254740991 frequency_penalty: default: 0 nullable: true type: number minimum: -2 maximum: 2 presence_penalty: default: 0 nullable: true type: number minimum: -2 maximum: 2 response_format: anyOf: - type: object properties: type: type: string enum: - text required: - type - type: object properties: type: type: string enum: - json_schema json_schema: type: object properties: description: type: string name: type: string schema: type: object properties: {} strict: anyOf: - type: boolean - type: string nullable: true enum: - null required: - name required: - type - json_schema - type: object properties: type: type: string enum: - json_object required: - type store: default: false nullable: true type: boolean stream: default: false nullable: true type: boolean stop: nullable: true anyOf: - type: string - type: array items: type: string logit_bias: default: null nullable: true type: object additionalProperties: type: integer minimum: -9007199254740991 maximum: 9007199254740991 logprobs: default: false nullable: true type: boolean max_tokens: nullable: true type: integer minimum: -9007199254740991 maximum: 9007199254740991 'n': default: 1 nullable: true type: integer minimum: 1 maximum: 128 prediction: nullable: true type: object properties: type: type: string enum: - content content: anyOf: - type: string - type: array items: type: object properties: type: type: string enum: - text text: type: string required: - type - text reasoning: type: string required: - type - content seed: nullable: true type: integer minimum: -9007199254740991 maximum: 9007199254740991 stream_options: anyOf: - type: object properties: include_usage: type: boolean include_obfuscation: type: boolean - type: string nullable: true enum: - null tools: type: array items: anyOf: - type: object properties: type: type: string enum: - function function: type: object properties: description: type: string name: type: string parameters: type: object properties: {} strict: anyOf: - type: boolean - type: string nullable: true enum: - null required: - name required: - type - function - type: object properties: type: type: string enum: - custom custom: type: object properties: name: type: string description: type: string format: anyOf: - type: object properties: type: type: string enum: - text required: - type - type: object properties: type: type: string enum: - grammar grammar: type: object properties: definition: type: string syntax: type: string enum: - lark - regex required: - definition - syntax required: - type - grammar required: - name required: - type - custom tool_choice: anyOf: - type: string enum: - none - auto - required - type: object properties: type: type: string enum: - allowed_tools allowed_tools: type: object properties: mode: type: string enum: - auto - required tools: type: array items: type: object properties: {} required: - mode - tools required: - type - allowed_tools - type: object properties: type: type: string enum: - function function: type: object properties: name: type: string required: - name required: - type - function - type: object properties: type: type: string enum: - custom custom: type: object properties: name: type: string required: - name required: - type - custom parallel_tool_calls: default: true type: boolean function_call: anyOf: - type: string enum: - none - auto - type: object properties: name: type: string required: - name functions: minItems: 1 maxItems: 128 type: array items: type: object properties: description: type: string name: type: string parameters: type: object properties: {} required: - name context_editing: type: object properties: enabled: type: boolean clear_tool_uses: type: object properties: trigger: type: integer minimum: -9007199254740991 maximum: 9007199254740991 keep: type: integer minimum: -9007199254740991 maximum: 9007199254740991 clear_at_least: type: integer minimum: -9007199254740991 maximum: 9007199254740991 exclude_tools: type: array items: type: string clear_tool_inputs: type: boolean additionalProperties: false clear_thinking: type: object properties: keep: anyOf: - type: integer minimum: -9007199254740991 maximum: 9007199254740991 - type: string enum: - all additionalProperties: false required: - enabled additionalProperties: false image_generation: type: object properties: aspect_ratio: type: string image_size: type: string required: - aspect_ratio - image_size required: - messages - model additionalProperties: false responses: '200': description: Request accepted ````