Skip to content
OpenKey

Mercury 2

InceptionReleased Mar 4, 2026

Mercury 2 is an extremely fast reasoning LLM, and the first reasoning diffusion LLM (dLLM). Instead of generating tokens sequentially, Mercury 2 produces and refines multiple tokens in parallel, achieving...

Try in playground
Context window
128K tokens
Max output
50K tokens
Input
text
Output
text
Tokenizer
Other
Released
Mar 4, 2026
Reasoning
optional

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$0.250$0.0075$0.258
Output$0.750$0.022$0.772
Cache read$0.025$0.0008$0.026

Benchmarks

Design Arena

CategoryEloWin rateRank
3Dmodels105424.8%#84
Codemodels104322%#93
Data vizmodels99319.1%#89
Game devmodels104421.4%#88
UI componentsmodels102220.5%#85
Websitesmodels103921.7%#94

Head-to-head preference voting. How we filter and rank

Supported parameters

  • include_reasoning
  • max_tokens
  • reasoning
  • response_format
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model inception/mercury-2.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "inception/mercury-2",
    "messages": [{"role": "user", "content": "Hello"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.openkey.ai/v1",
    api_key=os.environ["OPENKEY_API_KEY"],
)

completion = client.chat.completions.create(
    model="inception/mercury-2",
    messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.openkey.ai/v1",
  apiKey: process.env.OPENKEY_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "inception/mercury-2",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Mercury 2 cost via API?
Through OpenKey, Mercury 2 costs $0.258 per 1M input tokens and $0.772 per 1M output tokens. That is the provider price ($0.250 / $0.750) plus a flat 3% fee — nothing else.
What is Mercury 2's context window?
Mercury 2 accepts up to 128K tokens of context and returns up to 50K tokens per request.
Is Mercury 2 OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "inception/mercury-2" using any OpenAI SDK — only the base URL and API key change.
What inputs does Mercury 2 support?
Mercury 2 accepts text input and produces text output.