Skip to content
Relaykit

DeepSeek · DeepSeek · Fast

DeepSeek V4 Flash

New

Low-cost DeepSeek model with a 1M context window and optional thinking.

Model id

deepseek-v4-flash

Price per 1M tokens

Input
$0.24
Output
$0.96
Cached input
$0.004898% below input

Output is 4× the input rate. $1 covers about 1,388 prompts of 1,000 input + 500 output tokens. 1 credit = $1 of usage. All rates

Ways to pay

  • Pay as you goPrepaid balance at the rates above, top-ups from $3
  • Pro $5/monthWeekly allowance of 3.4M uncached input tokens, up to 13M with cache hits
  • Plus $9/monthWeekly allowance of 6.4M uncached input tokens, up to 25M with cache hits
  • Max $29/monthWeekly allowance of 21.2M uncached input tokens, up to 81M with cache hits

Plans are opening soon; until then every model is pay as you go. How plans will work

Start using DeepSeek V4 Flash

Set RELAYKIT_API_KEY to a key from your console, then run any example. Streaming is on so long answers are not cut off by idle-connection timeouts.

curl https://api.oneaiapikey.com/v1/chat/completions \
  -H "Authorization: Bearer $RELAYKIT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek-v4-flash",
    "stream": true,
    "messages": [{"role": "user", "content": "In two sentences, when should I use budget coding?"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.oneaiapikey.com/v1",
    api_key=os.environ["RELAYKIT_API_KEY"],
)

stream = client.chat.completions.create(
    model="deepseek-v4-flash",
    messages=[{"role": "user", "content": "In two sentences, when should I use budget coding?"}],
    stream=True,  # recommended for long outputs
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
import OpenAI from "openai";

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

const stream = await client.chat.completions.create({
  model: "deepseek-v4-flash",
  messages: [{ role: "user", content: "In two sentences, when should I use budget coding?" }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? "");
}

More: quickstart · API reference · try it in Chat first

Overview

When DeepSeek V4 Flash fits

DeepSeek V4 Flash is a fast, low-cost model from DeepSeek, available here under the exact model id “deepseek-v4-flash”. It is tuned for throughput, and its low rates make it a sensible default for high-volume, background or helper steps.

It costs $0.24 per million input tokens and $0.96 per million output tokens, so output is 4× the input rate. Both sides of the bill matter. For chat-style traffic with short replies, input usually ends up as the larger share; for code generation, output does. With a 3:1 input-to-output mix it is the lowest-cost model of the 11 on this site.

Cached input bills at $0.0048 per million tokens, 98% below the standard input rate. Workloads that resend the same system prompt, tool definitions and files on every turn, coding agents in particular, get the most from this.

It is served through the OpenAI-compatible format at https://api.oneaiapikey.com/v1, so any SDK or tool that lets you set a custom base URL, for example Codex CLI, Cursor and Cline, can use it. It is not offered on the Anthropic Messages endpoint; pick an Anthropic-format model for Claude Code.

Cost examples

What a workload costs

Worked from the published rates, with the arithmetic shown. Real numbers depend on prompt size and how much the model writes.

Model your own traffic

  • 1M input + 200k output tokens

    1 × $0.24 + 0.2 × $0.96

    $0.432

  • 1,000 chat replies (1.5k in, 400 out each)

    1000 × (0.0015 × $0.24 + 0.0004 × $0.96)

    $0.744

    About 1,344 replies per credit

  • One agent turn (30k in, 24k of it cached, 2k out)

    0.006 × $0.24 + 0.024 × $0.0048 + 0.002 × $0.96

    $0.003476

    $0.00912 with no cache hits. Writing tokens into the cache bills 1.25× the input rate (2× for a 1-hour cache) when the provider reports cache writes

Works with

Compatible agents 7

Coding tools that speak the OpenAI format. Each guide sets the base URL, key and this model id.

Similar models

Same tier, other vendors

Same key, same balance. Switching is a change to the model field.

Compare side by sideAll models

Try DeepSeek V4 Flash from a $3 top-up.

There is no sign-up credit: add $3 or more to your wallet and every request is billed at the rates above, with a receipt in your usage log.

DeepSeek V4 Flash is developed by DeepSeek. Model names and trademarks belong to their owners. Relaykit is an independent API gateway and is not affiliated with, endorsed by or sponsored by DeepSeek.