Go

Use the official openai-go library with api14. Point option.WithBaseURL at api14 and pass any model id (for example openai/gpt-5-mini) as the model.

Install

go get github.com/openai/openai-go
export API14_API_KEY="sk-api14-..."

Configure

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/openai/openai-go"
	"github.com/openai/openai-go/option"
)

var client = openai.NewClient(
	option.WithBaseURL("https://api14.com/api/v1/"),
	option.WithAPIKey(os.Getenv("API14_API_KEY")),
)

var ctx = context.Background()

// The snippets below run inside func main().

openai.NewClient() without options reads OPENAI_BASE_URL and OPENAI_API_KEY, so you can also configure it from the environment:

export OPENAI_BASE_URL="https://api14.com/api/v1/"
export OPENAI_API_KEY="sk-api14-..."

Chat

resp, err := client.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
	Model: "openai/gpt-5-mini",
	Messages: []openai.ChatCompletionMessageParamUnion{
		openai.UserMessage("Explain vector databases in two sentences."),
	},
})
if err != nil {
	panic(err)
}
fmt.Println(resp.Choices[0].Message.Content)

Streaming

stream := client.Chat.Completions.NewStreaming(ctx, openai.ChatCompletionNewParams{
	Model:    "anthropic/claude-sonnet-4.5",
	Messages: []openai.ChatCompletionMessageParamUnion{openai.UserMessage("Write a haiku about APIs.")},
})
for stream.Next() {
	chunk := stream.Current()
	if len(chunk.Choices) > 0 {
		fmt.Print(chunk.Choices[0].Delta.Content)
	}
}
if err := stream.Err(); err != nil {
	panic(err)
}

See Streaming.

Tool calling

params := openai.ChatCompletionNewParams{
	Model:    "openai/gpt-5-mini",
	Messages: []openai.ChatCompletionMessageParamUnion{openai.UserMessage("What's the weather in Istanbul?")},
	Tools: []openai.ChatCompletionToolParam{{
		Function: openai.FunctionDefinitionParam{
			Name:        "get_weather",
			Description: openai.String("Current weather for a city"),
			Parameters: openai.FunctionParameters{
				"type":       "object",
				"properties": map[string]any{"city": map[string]string{"type": "string"}},
				"required":   []string{"city"},
			},
		},
	}},
}

for {
	resp, err := client.Chat.Completions.New(ctx, params)
	if err != nil {
		panic(err)
	}
	msg := resp.Choices[0].Message
	if len(msg.ToolCalls) == 0 {
		fmt.Println(msg.Content)
		break
	}
	params.Messages = append(params.Messages, msg.ToParam())
	for _, call := range msg.ToolCalls {
		var args struct{ City string }
		json.Unmarshal([]byte(call.Function.Arguments), &args)
		params.Messages = append(params.Messages, openai.ToolMessage(getWeather(args.City), call.ID))
	}
}

getWeather is your function returning a string. See Tool calling.

Structured output

schema := map[string]any{
	"type": "object",
	"properties": map[string]any{
		"name": map[string]string{"type": "string"},
		"born": map[string]string{"type": "integer"},
	},
	"required":             []string{"name", "born"},
	"additionalProperties": false,
}

resp, err := client.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
	Model:    "openai/gpt-5-mini",
	Messages: []openai.ChatCompletionMessageParamUnion{openai.UserMessage("Extract: Ada Lovelace, born 1815.")},
	ResponseFormat: openai.ChatCompletionNewParamsResponseFormatUnion{
		OfJSONSchema: &openai.ResponseFormatJSONSchemaParam{
			JSONSchema: openai.ResponseFormatJSONSchemaJSONSchemaParam{
				Name: "person", Schema: schema, Strict: openai.Bool(true),
			},
		},
	},
})

var person struct {
	Name string `json:"name"`
	Born int    `json:"born"`
}
_ = json.Unmarshal([]byte(resp.Choices[0].Message.Content), &person)

See Structured outputs.

Image input

resp, err := client.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
	Model: "google/gemini-2.5-flash",
	Messages: []openai.ChatCompletionMessageParamUnion{
		openai.UserMessage([]openai.ChatCompletionContentPartUnionParam{
			openai.TextContentPart("What is in this picture?"),
			openai.ImageContentPart(openai.ChatCompletionContentPartImageImageURLParam{
				URL: "https://example.com/photo.jpg", // or a data:image/png;base64,... URL
			}),
		}),
	},
})

See Vision & files.

Extra parameters

Fields the SDK has no type for, reasoning, provider, models, are added with option.WithJSONSet:

resp, err := client.Chat.Completions.New(ctx, params,
	option.WithJSONSet("reasoning", map[string]any{"effort": "high"}),
	option.WithJSONSet("provider", map[string]any{"sort": "throughput"}),
)

Embeddings

emb, err := client.Embeddings.New(ctx, openai.EmbeddingNewParams{
	Model: "openai/text-embedding-3-small",
	Input: openai.EmbeddingNewParamsInputUnion{OfArrayOfStrings: []string{"The quick brown fox", "Lorem ipsum"}},
})
if err == nil {
	fmt.Println(len(emb.Data[0].Embedding))
}

Errors

API errors are returned as *openai.Error, which carries the HTTP status, the machine Code and the raw response:

import "errors"

var apiErr *openai.Error
if errors.As(err, &apiErr) {
	switch apiErr.StatusCode {
	case 402: // insufficient_balance
		fmt.Println("Balance too low, add funds:", apiErr.Code)
	case 429: // rate_limited or daily_limit_reached
		fmt.Println("Retry after", apiErr.Response.Header.Get("Retry-After"), "s:", apiErr.Code)
	}
}

See Errors.

Timeouts and retries

The client retries 408, 409, 429 and 5xx twice by default with exponential backoff. Set the retry count and a per-attempt timeout as client or request options, and bound the whole call with a context:

client := openai.NewClient(
	option.WithBaseURL("https://api14.com/api/v1/"),
	option.WithAPIKey(os.Getenv("API14_API_KEY")),
	option.WithMaxRetries(4),
	option.WithRequestTimeout(60*time.Second), // per attempt
)

ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute) // all attempts
defer cancel()

Retrying does not help with daily_limit_reached or insufficient_balance. See Rate limits.

All capabilities

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api14.com/api/v1",
  apiKey: process.env.API14_API_KEY,
});

const result = await client.chat.completions.create({
  "model": "openai/gpt-5-mini",
  "messages": [
    {
      "role": "user",
      "content": "Explain vector databases in two sentences."
    }
  ]
});
console.log(result.choices[0].message.content);