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The Fine-tuning API proxies fine-tuning job management to the configured provider. All endpoints follow the OpenAI fine-tuning API contract. The correct operation is determined automatically by the HTTP method and the presence of a :jobId path parameter.
Fine-tuning requires uploading a training file first. Use POST /v1/files with purpose=fine-tune to prepare your data.

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Endpoint routing

All fine-tuning requests are handled at /v1/fine_tuning/jobs/:jobId?/:cancel?. The gateway dispatches to the correct operation based on the method and path:
MethodPathOperation
GET/v1/fine_tuning/jobsList fine-tuning jobs
POST/v1/fine_tuning/jobsCreate a fine-tuning job
GET/v1/fine_tuning/jobs/:idRetrieve a fine-tuning job
POST/v1/fine_tuning/jobs/:id/cancelCancel a fine-tuning job

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List fine-tuning jobs

GET /v1/fine_tuning/jobs Returns a list of fine-tuning jobs for the configured provider.

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Request

​
x-portkey-provider
string
required
The provider to route the request to.
​
x-portkey-api-key
string
required
Your Portkey API key or provider API key.
​
limit
number
default:"20"
Maximum number of jobs to return.
​
after
string
Cursor for pagination. Pass the id of the last job from the previous page.

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Response

​
object
string
Always list.
​
data
array
Array of fine-tuning job objects.
​
has_more
boolean
Whether additional jobs are available.
curl https://your-gateway.example.com/v1/fine_tuning/jobs \
  -H "x-portkey-api-key: YOUR_API_KEY" \
  -H "x-portkey-provider: openai"

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Create a fine-tuning job

POST /v1/fine_tuning/jobs Creates a new fine-tuning job. The request body is forwarded directly to the provider.

​
Request

​
x-portkey-provider
string
required
The provider to route the request to.
​
x-portkey-api-key
string
required
Your Portkey API key or provider API key.
​
training_file
string
required
The ID of the uploaded training file (must have purpose=fine-tune).
​
model
string
required
The base model to fine-tune. For example, gpt-4o-mini-2024-07-18.
​
validation_file
string
The ID of an optional validation file.
​
hyperparameters
object
​
suffix
string
A string of up to 18 characters appended to the fine-tuned model name.
​
metadata
object
Optional key-value metadata to attach to the job.

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Response

​
id
string
Unique identifier for the fine-tuning job.
​
object
string
Always fine_tuning.job.
​
model
string
The base model being fine-tuned.
​
fine_tuned_model
string
The name of the fine-tuned model once training completes. null while in progress.
​
status
string
Current job status. Values: validating_files, queued, running, succeeded, failed, cancelled.
​
created_at
number
Unix timestamp when the job was created.
​
trained_tokens
number
Number of tokens used in training, or null if not yet available.
curl https://your-gateway.example.com/v1/fine_tuning/jobs \
  -X POST \
  -H "Content-Type: application/json" \
  -H "x-portkey-api-key: YOUR_API_KEY" \
  -H "x-portkey-provider: openai" \
  -d '{
    "training_file": "file-abc123",
    "model": "gpt-4o-mini-2024-07-18"
  }'

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Retrieve a fine-tuning job

GET /v1/fine_tuning/jobs/:id Retrieves details for a specific fine-tuning job. Use this to poll the status of an in-progress job.

​
Request

​
id
string
required
The ID of the fine-tuning job to retrieve.
​
x-portkey-provider
string
required
The provider to route the request to.
​
x-portkey-api-key
string
required
Your Portkey API key or provider API key.

​
Response

Returns a single fine-tuning job object. See Create a fine-tuning job for the full field list. 
curl https://your-gateway.example.com/v1/fine_tuning/jobs/ftjob-abc123 \
  -H "x-portkey-api-key: YOUR_API_KEY" \
  -H "x-portkey-provider: openai"

​
Cancel a fine-tuning job

POST /v1/fine_tuning/jobs/:id/cancel Cancels a fine-tuning job that is queued or running.
Once a job is cancelled it cannot be resumed. Any compute costs incurred up to the cancellation point may still apply.

​
Request

​
id
string
required
The ID of the fine-tuning job to cancel.
​
x-portkey-provider
string
required
The provider to route the request to.
​
x-portkey-api-key
string
required
Your Portkey API key or provider API key.

​
Response

Returns the updated fine-tuning job object with status: cancelled. 
curl https://your-gateway.example.com/v1/fine_tuning/jobs/ftjob-abc123/cancel \
  -X POST \
  -H "x-portkey-api-key: YOUR_API_KEY" \
  -H "x-portkey-provider: openai"

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