Pricing, context window, capabilities, and release date — pulled from each provider's public docs. Both are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.
Both models stream in parallel through your own AIgateway key. Tokens, latency, and cost update as they arrive.
| Grok 4.5 xai/grok-4.5 | Grok 4 Fast xai/grok-4-fast | |
|---|---|---|
| Provider | xAI | xAI |
| Family | Grok 4 | Grok 4 |
| Modality | text | text |
| Context window | 500,000 tok | 256,000 tok |
| Max output | 32,768 tok | 16,384 tok |
| Released | 2026-07-21 | 2025-09-19 |
| Input price | $1.00 /1M | $0.500 /1M |
| Output price | $1.00 /1M | $2.00 /1M |
| Cache read | — | — |
| Tools | — | yes |
| Streaming | yes | yes |
| Vision | yes | — |
| JSON mode | — | yes |
| Reasoning | — | — |
| Prompt caching | — | — |
xAI's Grok 4.5, a frontier model built for coding, agentic tasks, and knowledge work. Accepts text and image inputs, and supports function calling, structured outputs, and configurable reasoning effort (low, medium, high).
xAI Grok 4 Fast — low-latency variant.
# pip install aigateway-py openai
# aigateway-py: sub-accounts, evals, replays, jobs, webhook verify.
# openai SDK: chat/embeddings/images/audio — drop-in compat per our SDK's own guidance.
from openai import OpenAI
client = OpenAI(
base_url="https://api.aigateway.sh/v1",
api_key="sk-aig-...",
)
# Try Grok 4.5
client.chat.completions.create(
model="xai/grok-4.5",
messages=[{"role":"user","content":"hello"}],
)
# Try Grok 4 Fast — same client, same key
client.chat.completions.create(
model="xai/grok-4-fast",
messages=[{"role":"user","content":"hello"}],
)