Create Chat Completion

POST 
/chat/completions

Creates a model response for the given chat conversation.

Request

application/json

Body

required

messages

object[]

required

Possible values: >= 1

A list of messages comprising the conversation so far.

Array [

oneOf

System message

content stringrequired

The contents of the system message.

role stringrequired

Possible values: [system]

The role of the messages author, in this case system.

name string

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

User message

content Text content (string)required

The contents of the user message.

role stringrequired

Possible values: [user]

The role of the messages author, in this case user.

name string

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

Assistant message

content stringnullablerequired

The contents of the assistant message.

role stringrequired

Possible values: [assistant]

The role of the messages author, in this case assistant.

name string

An optional name for the participant. Provides the model information to differentiate between participants of the same role.

]

model stringrequired

Possible values: [deepseek-chat, deepseek-coder]

ID of the model to use. You can use either usedeepseek-coder or deepseek-chat.

frequency_penalty numbernullable

Possible values: >= -2 and <= 2

Default value: 0

Number between -2.0 and 2.0. Positive values penalize new tokens based on their existing frequency in the text so far, decreasing the model's likelihood to repeat the same line verbatim.

max_tokens integernullable

Possible values: > 1

The maximum number of tokens that can be generated in the chat completion.

The total length of input tokens and generated tokens is limited by the model's context length.

presence_penalty numbernullable

Possible values: >= -2 and <= 2

Default value: 0

Number between -2.0 and 2.0. Positive values penalize new tokens based on whether they appear in the text so far, increasing the model's likelihood to talk about new topics.

stop

object

Up to 8 sequences where the API will stop generating further tokens.

oneOf

MOD1

string

MOD2

Array [

string

]

stream booleannullable

If set, partial message deltas will be sent. Tokens will be sent as data-only server-sent events (SSE) as they become available, with the stream terminated by a data: [DONE] message.

temperature numbernullable

Possible values: <= 2

Default value: 1

What sampling temperature to use, between 0 and 2. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic.

We generally recommend altering this or top_p but not both.

top_p numbernullable

Possible values: <= 1

Default value: 1

An alternative to sampling with temperature, called nucleus sampling, where the model considers the results of the tokens with top_p probability mass. So 0.1 means only the tokens comprising the top 10% probability mass are considered.

We generally recommend altering this or temperature but not both.

logprobs booleannullable

Whether to return log probabilities of the output tokens or not. If true, returns the log probabilities of each output token returned in the content of message.

top_logprobs integernullable

Possible values: <= 20

An integer between 0 and 20 specifying the number of most likely tokens to return at each token position, each with an associated log probability. logprobs must be set to true if this parameter is used.

Responses

200 (No streaming)

OK, returns a chat completion object

application/json

Schema

Schema

id stringrequired

A unique identifier for the chat completion.

choices

object[]

required

A list of chat completion choices.

Array [

finish_reason stringrequired

Possible values: [stop, length, content_filter]

The reason the model stopped generating tokens. This will be stop if the model hit a natural stop point or a provided stop sequence, length if the maximum number of tokens specified in the request was reached, content_filter if content was omitted due to a flag from our content filters.

index integerrequired

The index of the choice in the list of choices.

message

object

required

A chat completion message generated by the model.

content stringnullablerequired

The contents of the message.

role stringrequired

Possible values: [assistant]

The role of the author of this message.

logprobs

object

nullable

required

Log probability information for the choice.

content

object[]

nullable

required

A list of message content tokens with log probability information.

Array [

token stringrequired

The token.

logprob numberrequired

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes integer[]nullablerequired

A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

top_logprobs

object[]

required

List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

Array [

token stringrequired

The token.

logprob numberrequired

The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes integer[]nullablerequired

A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

]

]

]

created integerrequired

The Unix timestamp (in seconds) of when the chat completion was created.

model stringrequired

The model used for the chat completion.

system_fingerprint stringrequired

This fingerprint represents the backend configuration that the model runs with.

object stringrequired

Possible values: [chat.completion]

The object type, which is always chat.completion.

usage

object

Usage statistics for the completion request.

completion_tokens integerrequired

Number of tokens in the generated completion.

prompt_tokens integerrequired

Number of tokens in the prompt.

total_tokens integerrequired

Total number of tokens used in the request (prompt + completion).

Example (from schema)

{
  "id": "string",
  "choices": [
    {
      "finish_reason": "stop",
      "index": 0,
      "message": {
        "content": "string",
        "role": "assistant"
      },
      "logprobs": {
        "content": [
          {
            "token": "string",
            "logprob": 0,
            "bytes": [
              0
            ],
            "top_logprobs": [
              {
                "token": "string",
                "logprob": 0,
                "bytes": [
                  0
                ]
              }
            ]
          }
        ]
      }
    }
  ],
  "created": 0,
  "model": "string",
  "system_fingerprint": "string",
  "object": "chat.completion",
  "usage": {
    "completion_tokens": 0,
    "prompt_tokens": 0,
    "total_tokens": 0
  }
}

Example

{
  "id": "930c60df-bf64-41c9-a88e-3ec75f81e00e",
  "choices": [
    {
      "finish_reason": "stop",
      "index": 0,
      "message": {
        "content": "Hello! How can I help you today?",
        "role": "assistant"
      }
    }
  ],
  "created": 1705651092,
  "model": "deepseek-chat",
  "object": "chat.completion",
  "usage": {
    "completion_tokens": 10,
    "prompt_tokens": 16,
    "total_tokens": 26
  }
}

200 (Streaming)

OK, returns a streamed sequence of chat completion chunk objects

text/event-stream

Schema

Schema

• Array [

id stringrequired

A unique identifier for the chat completion. Each chunk has the same ID.

choices

object[]

required

A list of chat completion choices.

Array [

delta

object

required

A chat completion delta generated by streamed model responses.

content stringnullable

The contents of the chunk message.

role string

Possible values: [assistant]

The role of the author of this message.

finish_reason stringnullablerequired

Possible values: [stop, length, content_filter]

The reason the model stopped generating tokens. This will be stop if the model hit a natural stop point or a provided stop sequence, length if the maximum number of tokens specified in the request was reached, content_filter if content was omitted due to a flag from our content filters.

index integerrequired

The index of the choice in the list of choices.

]

created integerrequired

The Unix timestamp (in seconds) of when the chat completion was created. Each chunk has the same timestamp.

model stringrequired

The model to generate the completion.

system_fingerprint stringrequired

This fingerprint represents the backend configuration that the model runs with.

object stringrequired

Possible values: [chat.completion.chunk]

The object type, which is always chat.completion.chunk.

• ]

Example

data: {"id": "1f633d8bfc032625086f14113c411638", "choices": [{"index": 0, "delta": {"content": "", "role": "assistant"}, "finish_reason": null, "logprobs": null}], "created": 1718345013, "model": "deepseek-chat", "system_fingerprint": "fp_a49d71b8a1", "object": "chat.completion.chunk", "usage": null}

data: {"choices": [{"delta": {"content": "Hello", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": "!", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " How", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " can", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " I", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " assist", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " you", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": " today", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": "?", "role": "assistant"}, "finish_reason": null, "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1"}

data: {"choices": [{"delta": {"content": "", "role": null}, "finish_reason": "stop", "index": 0, "logprobs": null}], "created": 1718345013, "id": "1f633d8bfc032625086f14113c411638", "model": "deepseek-chat", "object": "chat.completion.chunk", "system_fingerprint": "fp_a49d71b8a1", "usage": {"completion_tokens": 9, "prompt_tokens": 17, "total_tokens": 26}}

data: [DONE]

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