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POST
/
v1
/
chat
/
completions
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." }
    ]
  }'
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. 
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." }
    ]
  }'

Body

application/json
​
messages
object[]
required
Minimum length: 1
  • Option 1
  • Option 2
  • Option 3
  • Option 4
  • Option 5
  • Option 6
​
model
string
required
​
metadata
​
top_logprobs
integer | null
Required range: 0 <= x <= 20
​
temperature
​
top_p
​
user
string
​
safety_identifier
string
​
prompt_cache_key
string
​
cache_control
object
​
service_tier
Available options:
auto,
default,
flex,
scale,
priority
​
modalities
​
verbosity
Available options:
low,
medium,
high
​
reasoning_effort
Available options:
minimal,
low,
medium,
high
​
max_completion_tokens
integer | null
Required range: -9007199254740991 <= x <= 9007199254740991
​
frequency_penalty
number | null
default:0
Required range: -2 <= x <= 2
​
presence_penalty
number | null
default:0
Required range: -2 <= x <= 2
​
response_format
object
  • Option 1
  • Option 2
  • Option 3
​
store
boolean | null
default:false
​
stream
boolean | null
default:false
​
stop
​
logit_bias
object | null
​
logprobs
boolean | null
default:false
​
max_tokens
integer | null
Required range: -9007199254740991 <= x <= 9007199254740991
​
n
integer | null
default:1
Required range: 1 <= x <= 128
​
prediction
object | null
​
seed
integer | null
Required range: -9007199254740991 <= x <= 9007199254740991
​
stream_options
​
tools
object[]
  • Option 1
  • Option 2
​
tool_choice
Available options:
none,
auto,
required
​
parallel_tool_calls
boolean
default:true
​
function_call
Available options:
none,
auto
​
functions
object[]
Required array length: 1 - 128 elements

Response

200

Request accepted