Which is cheaper, GPT-6 Luna or DeepSeek V4 Flash 0423?

DeepSeek V4 Flash 0423 is the cheaper of the two: one 1,000-word request costs about 123 toman, about 2.2× cheaper than GPT-6 Luna.

Which one has the larger context window?

GPT-6 Luna, with 1,050,000 tokens.

Can I use GPT-6 Luna and DeepSeek V4 Flash 0423 with one API key?

Yes. An uttapen key reaches every model unless you gave it an allowed-models list, and each request is charged in toman to the same wallet; only the model value changes.

GPT-6 Luna vs DeepSeek V4 Flash 0423

Both sit behind the same key and the same code on uttapen — the only thing that changes is the model string, so you can run each of them against your own workload without touching anything else. On cost, DeepSeek V4 Flash 0423 comes out about 2.2× cheaper.

Feature	GPT-6 Luna	DeepSeek V4 Flash 0423
Provider	OpenAI	DeepSeek
Model id	openai/gpt-6-luna	deepseek/deepseek-v4-flash
Context	1,050,000 tokens	1,048,576 tokens
Max output	128,000 tokens	943,717 tokens
Input / 1M tokens	34,622 toman	31,506 toman
Output / 1M tokens	173,110 toman	63,012 toman
≈ one 1,000-word request	270 toman	123 toman
Input caching	3,462 toman / 1M	6,301 toman / 1M
Image input	Yes	No
File input	Yes	No
Tool calling	Yes	Yes
JSON output	Yes	Yes
Reasoning mode	Yes	Yes

Which one for what?

GPT-6 Luna

Multi-step problems, maths, and tracking down a bug
Whole documents or a codebase in a single request
Reading screenshots, invoices, and scanned forms
Agents that call your own APIs and database
High-volume work where cost per call decides

270 toman per 1,000 words · Model page

DeepSeek V4 Flash 0423

Multi-step problems, maths, and tracking down a bug
Whole documents or a codebase in a single request
Agents that call your own APIs and database
High-volume work where cost per call decides

123 toman per 1,000 words · Model page

Run both with the same code

Swap the model value between the two ids and send the same request twice; what each answer cost comes back in the X-Uttapen-Cost-Toman header.

curlPythonNode.jsPHPGo

curl https://api.uttapen.ir/v1/chat/completions \
  -H "Authorization: Bearer sk-up-…" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-6-luna",
    "messages": [{"role": "user", "content": "Introduce yourself."}],
    "stream": true
  }'

from openai import OpenAI

client = OpenAI(
    base_url="https://api.uttapen.ir/v1",
    api_key="sk-up-…",
)

stream = client.chat.completions.create(
    model="openai/gpt-6-luna",
    messages=[{"role": "user", "content": "Introduce yourself."}],
    stream=True,
)
for chunk in stream:
    print(chunk.choices[0].delta.content or "", end="", flush=True)

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.uttapen.ir/v1",
  apiKey: "sk-up-…",
});

const stream = await client.chat.completions.create({
  model: "openai/gpt-6-luna",
  messages: [{ role: "user", content: "Introduce yourself." }],
  stream: true,
});
for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? "");
}

<?php
// composer require openai-php/client guzzlehttp/guzzle
$client = OpenAI::factory()
    ->withBaseUri('https://api.uttapen.ir/v1')
    ->withApiKey('sk-up-…')
    ->make();

$result = $client->chat()->create([
    'model' => 'openai/gpt-6-luna',
    'messages' => [['role' => 'user', 'content' => 'Introduce yourself.']],
]);
echo $result->choices[0]->message->content;

package main

import (
	"context"
	"fmt"

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

func main() {
	client := openai.NewClient(
		option.WithBaseURL("https://api.uttapen.ir/v1"),
		option.WithAPIKey("sk-up-…"),
	)
	resp, err := client.Chat.Completions.New(context.Background(), openai.ChatCompletionNewParams{
		Model:    "openai/gpt-6-luna",
		Messages: []openai.ChatCompletionMessageParamUnion{openai.UserMessage("Introduce yourself.")},
	})
	if err != nil {
		panic(err)
	}
	fmt.Println(resp.Choices[0].Message.Content)
}

model = "deepseek/deepseek-v4-flash"

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Frequently asked

Which is cheaper, GPT-6 Luna or DeepSeek V4 Flash 0423?: DeepSeek V4 Flash 0423 is the cheaper of the two: one 1,000-word request costs about 123 toman, about 2.2× cheaper than GPT-6 Luna.
Which one has the larger context window?: GPT-6 Luna, with 1,050,000 tokens.
Can I use GPT-6 Luna and DeepSeek V4 Flash 0423 with one API key?: Yes. An uttapen key reaches every model unless you gave it an allowed-models list, and each request is charged in toman to the same wallet; only the model value changes.

More comparisons: all pairs · model rankings · full catalogue

base_url = https://api.uttapen.ir/v1