DeepSeek: DeepSeek V3.1 Terminus

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DeepSeek V3.1 Terminus is DeepSeek's 671B-parameter hybrid reasoning model, released 2025-09 as a refinement of DeepSeek V3.1 with only 37B active parameters. It addresses language consistency and agent capability issues while improving coding and search agent performance, matching DeepSeek-R1 on difficult benchmarks with faster response times.

MirAPI doesn’t offer this model. The prices shown are the official list prices.

Modalities
inTextoutText
Price / 1M
$0.27 / $1.00
Context
164K
Released
Sep 22, 2025
Knowledge cutoff
Mar 31, 2025

Capabilities

ReasoningTool useStructured output

Parameters

Request parameters this model accepts through the API.

frequency_penaltyinclude_reasoningmax_tokensreasoningresponse_formatstopstructured_outputstemperaturetool_choicetoolstop_ktop_p

Benchmarks

bar = score (0–100) · ▏ median

Scores come from vendor reports and public leaderboards, not private evals.

Intelligence Index
General ability
14.8
#101
Coding Index
Code
43.5
#53
Agentic Index
Agentic
6.8
#46
GPQA Diamond
Science QA
76.8
#86
τ-bench (airline)
Agentic tool use
70.4
#67

Showcase

Every chat model gets the same three fixed prompts. Outputs are archived verbatim, so you can copy a prompt and reproduce the result.

Task prompt · identical for all models
Build a single-file HTML page using three.js from a CDN: a low-poly planet with a tilted ring of ~200 orbiting particles, a soft key light plus rim light, slow auto-rotation, and drag-to-orbit controls. No build tools — one file only.
Archived output
Archive not published yet

Every model will run this exact prompt, and its output will appear here verbatim with token counts and the cost per run.

Quick start

import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.mirapi.ai/v1",   # changed
    api_key=os.environ["MIRAPI_API_KEY"],   # changed
)

resp = client.chat.completions.create(
    model="",
    messages=[{"role": "user", "content": "Hello"}],
)
Wire DeepSeek V3.1 Terminus into your product

1M free tokens to start, no card required. It’s OpenAI-compatible, so you only change the base URL.

Start free