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Grok 4.3 vs Claude Sonnet 4.6: Which AI Model Should You Choose?

Pricing, context windows, latency, capabilities, and a one-line code switch — everything you need to pick the right model.

xAI
Multimodal
vs
Anthropic
Multimodal
Verdict

Choose Grok 4.3 for cost-sensitive workloads — it is roughly 3.0× cheaper on input tokens. Choose Claude Sonnet 4.6 when you need its broader capabilities or stronger benchmarks.

Choose Grok 4.3 for long documents (1.0M tokens context). Choose Claude Sonnet 4.6 for shorter prompts where the smaller window keeps latency and cost down.

Side-by-side specs

SpecGrok 4.3Claude Sonnet 4.6
ProviderxAIAnthropic
CategoryMultimodalMultimodal
Input cost / 1M tokens€0.0010€0.0030
Output cost / 1M tokens€0.0030€0.015
Context window1.0M tokens200K tokens
Max output tokens1,000,00064,000
Avg. latency——
FeaturedYesYes
NewYesYes
Capabilities
text
image
text
image

Pricing example

A typical chat workload of 100,000 input tokens plus 50,000 output tokens.

Grok 4.3
€0.0003

100K in × €0.0010 + 50K out × €0.0030

Claude Sonnet 4.6
€0.0011

100K in × €0.0030 + 50K out × €0.015

For this workload, Grok 4.3 is cheaper than Claude Sonnet 4.6 by €0.0008 per request.

Switch in one line

Both models live behind Railwail's OpenAI-compatible endpoint. Replace the model string and you are done.

JavaScript / TypeScript
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.RAILWAIL_API_KEY,
  baseURL: "https://railwail.com/v1",
});

// Before — using Grok 4.3
let r = await client.chat.completions.create({
  model: "grok-4.3",
  messages: [{ role: "user", content: "Hello" }],
});

// After — switched to Claude Sonnet 4.6
r = await client.chat.completions.create({
  model: "claude-sonnet-4-6-20260217",
  messages: [{ role: "user", content: "Hello" }],
});
Python
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["RAILWAIL_API_KEY"],
    base_url="https://railwail.com/v1",
)

# Before — using Grok 4.3
r = client.chat.completions.create(
    model="grok-4.3",
    messages=[{"role": "user", "content": "Hello"}],
)

# After — switched to Claude Sonnet 4.6
r = client.chat.completions.create(
    model="claude-sonnet-4-6-20260217",
    messages=[{"role": "user", "content": "Hello"}],
)
cURL
# Before — using Grok 4.3
curl https://railwail.com/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4.3",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

# After — switched to Claude Sonnet 4.6
curl https://railwail.com/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6-20260217",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Which one wins for...

Quick verdicts derived from public specs. Always validate on your own workload.

Coding
Grok 4.3

Higher coding category match or larger context wins.

Writing
Grok 4.3

Bigger context window helps maintain long-form coherence.

Long documents
Grok 4.3

The larger context window is the deciding factor.

Vision
Tie

Multimodal/vision support is required for image inputs.

Real-time chat
Tie

Lower average latency wins for interactive UX.

Cost-sensitive
Grok 4.3

The model with the lower input-token price wins.

Frequently asked questions

Which is cheaper, Grok 4.3 or Claude Sonnet 4.6?
Grok 4.3 is cheaper. On a 100K input + 50K output example, Grok 4.3 costs about €0.0003 versus €0.0011 for Claude Sonnet 4.6 — a saving of €0.0008.
Which has more context, Grok 4.3 or Claude Sonnet 4.6?
Grok 4.3 has the larger context window at 1.0M tokens, compared to 200K tokens for Claude Sonnet 4.6.
Is Grok 4.3 better than Claude Sonnet 4.6 for coding?
For coding-heavy workloads we lean toward Grok 4.3 on this comparison — it scores higher on the relevant heuristics (category, tags, or context window). Both models are usable for code via Railwail's OpenAI-compatible endpoint, so the safest path is to A/B test on your own prompts.
Can I use both Grok 4.3 and Claude Sonnet 4.6 via Railwail?
Yes. Both Grok 4.3 and Claude Sonnet 4.6 are accessible through a single Railwail API key and the OpenAI-compatible /v1/chat/completions endpoint. You only change the "model" parameter to switch between them — no SDK swap, no separate billing.
How do I switch from Grok 4.3 to Claude Sonnet 4.6?
Replace the model identifier "grok-4.3" with "claude-sonnet-4-6-20260217" in your request payload. Everything else — API key, base URL, request shape — stays the same. See the code example on this page for the exact one-line change.

Try Grok 4.3 and Claude Sonnet 4.6 side by side

One API key, one endpoint, both models. Start free — no credit card required.

Get Started FreeView Grok 4.3View Claude Sonnet 4.6