grok-4.20-0309-reasoning is xAI's reasoning-focused Grok variant, built for document-heavy analysis and long-horizon tool use.
Channels
Every channel serves the same model, but they differ in price and stability. On each API key in the Platform, you pick a primary and a backup channel per vendor, and each billing line shows which channel served the request.
Context pricing
This model’s price depends on how much input context a request carries. The headline price is the cheapest band, and a longer prompt moves the whole request into a higher one.
Capabilities
Cost calculator
Pick a channel and a usage scenario, then drag the sliders to match your workload. Each scenario assumes a different prompt-cache hit rate.
Showcase
Every chat model gets the same three fixed prompts. Outputs are archived verbatim, so you can copy a prompt and reproduce the result.
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.
Every model will run this exact prompt, and its output will appear here verbatim with token counts and the cost per run.
Find the sum of all positive integers n such that n² + 85n + 2017 is a perfect square. Show your reasoning, then give only the final answer on the last line.
Every model will run this exact prompt, and its output will appear here verbatim with token counts and the cost per run.
Extract strict JSON {vendor, invoice_no, issue_date, currency, total, line_items:[{desc, qty, unit_price}]} from the invoice text. Output JSON only.
"Northwind Cloud Ltd. — Invoice NW-20847, issued 12 Mar 2026. 3× GPU-hour bundle at $18.40, 1× object storage 2TB at $9.90. Total $65.10 (USD)."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="grok-4.20-0309-reasoning", messages=[{"role": "user", "content": "Hello"}], )
import OpenAI from "openai"; const client = new OpenAI({ baseURL: "https://api.mirapi.ai/v1", // changed apiKey: process.env.MIRAPI_API_KEY, // changed }); const res = await client.chat.completions.create({ model: "grok-4.20-0309-reasoning", messages: [{ role: "user", content: "Hello" }], });
curl https://api.mirapi.ai/v1/chat/completions \ -H "Authorization: Bearer $MIRAPI_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "grok-4.20-0309-reasoning", "messages": [{"role": "user", "content": "Hello"}] }'
# ~/.zshrc export ANTHROPIC_BASE_URL="https://api.mirapi.ai" export ANTHROPIC_AUTH_TOKEN="$MIRAPI_API_KEY" # start as usual (model names stay the same) claude --model grok-4.20-0309-reasoning
# ~/.codex/config.toml model_provider = "mirapi" model = "grok-4.20-0309-reasoning" [model_providers.mirapi] name = "MirAPI" base_url = "https://api.mirapi.ai/v1" env_key = "MIRAPI_API_KEY" wire_api = "responses"
Links
1M free tokens to start, no card required. It’s OpenAI-compatible, so you only change the base URL.