Completions
Legacy

Given a prompt, the model will return one or more predicted completions along with the probabilities of alternative tokens at each position. Most developer should use our Chat Completions API to leverage our best and newest models.source

Create completion
Legacy

post https://api.openai.com/v1/completions

Creates a completion for the provided prompt and parameters.source

Request body

ID of the model to use. You can use the List models API to see all of your available models, or see our Model overview for descriptions of them.source

The prompt(s) to generate completions for, encoded as a string, array of strings, array of tokens, or array of token arrays.source

Note that <|endoftext|> is the document separator that the model sees during training, so if a prompt is not specified the model will generate as if from the beginning of a new document.source

Generates best_of completions server-side and returns the "best" (the one with the highest log probability per token). Results cannot be streamed.source

When used with n, best_of controls the number of candidate completions and n specifies how many to return – best_of must be greater than n.source

Note: Because this parameter generates many completions, it can quickly consume your token quota. Use carefully and ensure that you have reasonable settings for max_tokens and stop.source

Echo back the prompt in addition to the completionsource

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.source

See more information about frequency and presence penalties.source

Modify the likelihood of specified tokens appearing in the completion.source

Accepts a JSON object that maps tokens (specified by their token ID in the GPT tokenizer) to an associated bias value from -100 to 100. You can use this tokenizer tool to convert text to token IDs. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.source

As an example, you can pass {"50256": -100} to prevent the <|endoftext|> token from being generated.source

Include the log probabilities on the logprobs most likely output tokens, as well the chosen tokens. For example, if logprobs is 5, the API will return a list of the 5 most likely tokens. The API will always return the logprob of the sampled token, so there may be up to logprobs+1 elements in the response.source

The maximum value for logprobs is 5.source

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

The token count of your prompt plus max_tokens cannot exceed the model's context length. Example Python code for counting tokens.source

How many completions to generate for each prompt.source

Note: Because this parameter generates many completions, it can quickly consume your token quota. Use carefully and ensure that you have reasonable settings for max_tokens and stop.source

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.source

See more information about frequency and presence penalties.source

If specified, our system will make a best effort to sample deterministically, such that repeated requests with the same seed and parameters should return the same result.source

Determinism is not guaranteed, and you should refer to the system_fingerprint response parameter to monitor changes in the backend.source

Up to 4 sequences where the API will stop generating further tokens. The returned text will not contain the stop sequence.source

Whether to stream back partial progress. If set, tokens will be sent as data-only server-sent events as they become available, with the stream terminated by a data: [DONE] message. Example Python code.source

Options for streaming response. Only set this when you set stream: true.source

The suffix that comes after a completion of inserted text.source

This parameter is only supported for gpt-3.5-turbo-instruct.source

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.source

We generally recommend altering this or top_p but not both.source

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.source

We generally recommend altering this or temperature but not both.source

A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. Learn more.source

Returns

Returns a completion object, or a sequence of completion objects if the request is streamed.source

Example request
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curl https://api.openai.com/v1/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -d '{
    "model": "gpt-3.5-turbo-instruct",
    "prompt": "Say this is a test",
    "max_tokens": 7,
    "temperature": 0
  }'
Response
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{
  "id": "cmpl-uqkvlQyYK7bGYrRHQ0eXlWi7",
  "object": "text_completion",
  "created": 1589478378,
  "model": "gpt-3.5-turbo-instruct",
  "system_fingerprint": "fp_44709d6fcb",
  "choices": [
    {
      "text": "\n\nThis is indeed a test",
      "index": 0,
      "logprobs": null,
      "finish_reason": "length"
    }
  ],
  "usage": {
    "prompt_tokens": 5,
    "completion_tokens": 7,
    "total_tokens": 12
  }
}

The completion object
Legacy

Represents a completion response from the API. Note: both the streamed and non-streamed response objects share the same shape (unlike the chat endpoint).source

A unique identifier for the completion.source

The list of completion choices the model generated for the input prompt.source

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

The model used for completion.source

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

Can be used in conjunction with the seed request parameter to understand when backend changes have been made that might impact determinism.source

The object type, which is always "text_completion"source

Usage statistics for the completion request.source

OBJECT The completion object
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{
  "id": "cmpl-uqkvlQyYK7bGYrRHQ0eXlWi7",
  "object": "text_completion",
  "created": 1589478378,
  "model": "gpt-4-turbo",
  "choices": [
    {
      "text": "\n\nThis is indeed a test",
      "index": 0,
      "logprobs": null,
      "finish_reason": "length"
    }
  ],
  "usage": {
    "prompt_tokens": 5,
    "completion_tokens": 7,
    "total_tokens": 12
  }
}