Grok 4.3 hits GA on Amazon Bedrock with 1M context on the new Mantle inference engine

What's new

• First xAI model in Bedrock — GA since June 15, announced June 17
• 1M context window with configurable reasoning effort (none / low / medium / high)
• Mantle engine: new price-performance inference layer in Bedrock with tool calling, structured output, streaming
• Pricing: $1.25 input / $2.50 output per MTok, $0.20 cached — cheapest US-lab frontier reasoner on Bedrock
• Use cases: contract review, case-law research, credit-agreement analysis, financial document Q&A
• Claimed lowest hallucination rate among frontier models (per xAI)

Why it matters

AWS-anchored enterprises get a new frontier option next to Anthropic, Mistral and Meta. Pricing well below Claude or GPT-5 in Bedrock unlocks long-context workloads that were previously uneconomic.

How to try it

Enable Grok 4.3 in the Bedrock model catalog in supported US regions. Bill via standard Bedrock on-demand or Priority / Flex service tier.