Grok 4.3 API
Million-token context at roughly half the flagship rate.
Model spec
- Input
- $1.25per 1M tokens
- Output
- $2.50per 1M tokens
- Context
- 1M
Prompts over 200K tokens bill at $2.50 / $5.00.
Model ID
OpenAI-compatible · api.companyfabric.com/v1
Overview
About Grok 4.3
Million-token context at roughly half the flagship rate. Every model on CompanyFabric shares the same API key, billing balance, and rate-limit envelope, one integration covers the entire library.
Facts
At a glance
Availability
Live
Added 30 Aug 2026
Pricing
$1.25 in · $2.50 out
Per 1M tokens, metered exactly per call
Context window
1M tokens
Commercial use
See license
Commercial output use permitted per xAI terms.
Variants
All endpoints
Quickstart
How to use the Grok 4.3 API
- 1
Create a free CompanyFabric account, starter credits are included, no card required.
- 2
Copy your API key from the dashboard. One key covers every model in the library.
- 3
Point any OpenAI SDK at api.companyfabric.com/v1 and set model to "xai/grok-4-3".
- 4
Read the exact metered cost of the call from the response, the same number shown in the playground.
Use cases
What teams build with it
Agents & copilots
Drive agent loops, tool calls, and user-facing assistants over the OpenAI-compatible endpoint.
agentstool useassistants
Content pipelines
Summarization, rewriting, and structured generation at metered per-token cost.
contentsummarization
Extraction & classification
Turn unstructured input into typed JSON with schema-constrained output.
extractionjson mode
Get better output
Prompting tips
- State the output format before the task, models follow contracts declared early.
- Few-shot beats description: two worked examples outperform a paragraph of rules.
- Cap output length explicitly when cost matters; output tokens dominate most bills.
Exact, metered, prepaid
Grok 4.3 pricing
Grok 4.3 pricing is per token: $1.25 / M input · $2.5 / M output. Output tokens cost 2× input tokens, so long generations, not long prompts, are what actually drive most bills. A typical call with a 2k-token prompt and a 1k-token answer costs about $0.0050.
Every call is metered exactly and attributed to your key, the dashboard, the API usage response, and your invoice all read from the same ledger row. Cap any key's monthly spend with a budget cap, and bring your own provider key (BYOK) at 0% platform fee if you already have a direct contract.
Starter credits
Use Grok 4.3 free
Your CompanyFabric starter credits cover your first Grok 4.3 calls at no cost, create a free account, no card required, and the credits apply to Grok 4.3 and every other model on the key. When they run out, prepaid credits or BYOK (0% fee) take over with no plan to pick.
Production-grade
Code samples
import OpenAI from "openai"
const client = new OpenAI({
baseURL: "https://api.companyfabric.com/v1",
apiKey: process.env.COMPANYFABRIC_API_KEY,
})
const res = await client.chat.completions.create({
model: "xai/grok-4-3",
max_tokens: 1024,
temperature: 0.7,
messages: [{ role: "user", content: "Say hello from the fabric." }],
})
console.log(res.choices[0].message.content)Playground
Try it in the browser
Comparisons
Grok 4.3 vs the alternatives
Grok 4.3 vs Claude Sonnet 4.5
Grok 4.3 and Claude Sonnet 4.5 compete for the same text workloads. Both run behind the same CompanyFabric key at exact metered prices, A/B them on your real prompts and let the outputs decide, then switch with a one-line change.
Full comparison: Grok 4.3 vs Claude Sonnet 4.5 →Grok 4.3 vs GPT-5.5
Grok 4.3 and GPT-5.5 compete for the same text workloads. Both run behind the same CompanyFabric key at exact metered prices, A/B them on your real prompts and let the outputs decide, then switch with a one-line change.
Full comparison: Grok 4.3 vs GPT-5.5 →Compare
Grok 4.3 head to head
FAQ
Frequently asked questions
How much does the Grok 4.3 API cost?
$1.25 / M input · $2.5 / M output. Every call is metered exactly and shown before you run it.
How do I get a Grok 4.3 API key?
Create a CompanyFabric account, and one key unlocks Grok 4.3 and every other model in the library. Free starter credits are included, no subscription, no card required to try it.
Why use Grok 4.3 on CompanyFabric instead of going direct?
One key, one prepaid balance, and one rate-limit envelope across the whole library, at pricing at parity with or below the direct API. Model switching is a one-line change, and BYOK routing is 0% fee.
Is the API OpenAI-compatible?
Yes, point any OpenAI SDK at api.companyfabric.com/v1 and set model to "xai/grok-4-3".
Can I use the output commercially?
Commercial output use permitted per xAI terms.
How does billing work?
Prepaid credits via card, or BYOK with your own provider keys at 0% platform fee. No subscription required; balances never expire.
Provider
About xAI
One key. Every model. Exact prices.
Run Grok 4.3 with free starter credits. Free starter credits included, no subscription required.