curl --request GET \
  --url https://api.tokenfactory.nebius.com/v1/fine_tuning/jobs/{job_id}/checkpoints/{checkpoint_id} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "created_at": 123,
  "fine_tuned_model_checkpoint": "<string>",
  "fine_tuning_job_id": "<string>",
  "metrics": {
    "full_valid_loss": 123,
    "full_valid_mean_token_accuracy": 123,
    "step": 123,
    "train_loss": 123,
    "train_mean_token_accuracy": 123,
    "valid_loss": 123,
    "valid_mean_token_accuracy": 123
  },
  "object": "fine_tuning.job.checkpoint",
  "step_number": 123
}