Implementation:Promptfoo Promptfoo loadApiProvider

Knowledge Sources	Promptfoo Promptfoo Providers
Domains	Provider_Management, Evaluation
Last Updated	2026-02-14 08:00 GMT

Overview

Concrete tool for resolving provider identifier strings into instantiated ApiProvider objects, provided by the Promptfoo framework.

Description

The loadApiProvider function is the single entry point for provider instantiation. It accepts a provider path string and optional context, then routes through cloud providers, file-based configs, and a registry of 70+ built-in provider factories to create the appropriate ApiProvider instance.

Usage

Import this function when you need to instantiate a provider from a config string. This is used internally by the evaluation pipeline and can also be called directly for custom integrations.

Code Reference

Source Location

Repository: promptfoo
File: src/providers/index.ts
Lines: L31-177

Signature

export async function loadApiProvider(
  providerPath: string,
  context: LoadApiProviderContext = {},
): Promise<ApiProvider>

Import

import { loadApiProvider } from './providers';

I/O Contract

Inputs

Name	Type	Required	Description
providerPath	string	Yes	Provider identifier (e.g., 'openai:gpt-4', 'file://provider.yaml', 'python:my_provider.py')
context	LoadApiProviderContext	No	Loading context with options, basePath, and env overrides

Outputs

Name	Type	Description
(return)	ApiProvider	Instantiated provider with callApi(), id(), and optional embedding/classification methods

Usage Examples

Load OpenAI Provider

import { loadApiProvider } from './providers';

const provider = await loadApiProvider('openai:gpt-4o', {
  options: {
    config: { temperature: 0.7 },
  },
  env: { OPENAI_API_KEY: process.env.OPENAI_API_KEY },
});

const result = await provider.callApi('What is 2+2?');
console.log(result.output);

Load Python Custom Provider

const provider = await loadApiProvider('python:my_evaluator.py', {
  basePath: '/path/to/project',
});

Related Pages

Implements Principle

Principle:Promptfoo_Promptfoo_Provider_Resolution

Requires Environment

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