xAI

Grok Build

Grok Build is a text-only, tool-native model optimized for fast, agentic coding workflows. Developers building automated debugging pipelines or multi-step software agents should use it for rapid tool execution and structured reasoning.

Modalities

Text+Image → Text

Input

$1.389 /1M

Output

$2.777 /1M

Cached input

$0.1389 /1M90% off

Context

256K

Speed

fast

Performance

Live production data from real requests on Kyma — not synthetic benchmarks.

Rank

#28

of 87 active models

Tokens served

909.2K

all-time

Success rate

100%

last 7 days

Median throughput165 tok/s

Total requests148

Platform share0.0%

Tokens · last 15 daysJul 19 → Aug 2

Pricing

Pay per token. Cached input is billed at 10% of the input rate.

$1.389 /1M input$2.777 /1M output

Hobby10 req/day · 2K in / 500 out

~$1.25/mo

Production1,000 req/day · 2K in / 500 out

~$125/mo

Scale20,000 req/day · 2K in / 500 out

~$2,500/mo

+ Estimate your workload

Requests / day1,000

Input tokens / request2,000

Output tokens / request500

Cache hit rate30%

Estimated monthly cost

$102

$3.42 / day on Grok Build

Same workload on:

Grok 4.20 Multi-Agent$152+48%

Grok 4.20$152+48%

Estimates use list pricing with cached input billed at the 90%-discount rate. Actual bills depend on real token counts — every response includes its exact cost.

When to use Grok Build

Updated 2026-07-31

Where this model earns its cost — and where it doesn't.

Created by xAI, this model specializes in software development tasks. It handles tool calls natively, supports structured outputs, and includes built-in reasoning capabilities. It operates exclusively with text inputs and outputs, with a 256,000-token context window and a 32,768-token maximum output limit.

On Kyma, requests route through an OpenAI-compatible endpoint using a single API key. The platform provides automatic failover if a serving path degrades, and every response returns the exact token cost in usage.cost alongside the X-Kyma-Model header. Prompt caching is supported, billing repeated prefixes at 10% of the standard input rate. New accounts include a $0.50 credit.

It does not process images, audio, or other non-text modalities. While optimized for speed and tool use, its output length caps at 32,768 tokens, which may require chunking for very long codebase generation or extensive documentation tasks.

Agentic Software Development

Automates multi-step coding tasks by chaining tool calls and reasoning loops.

Rapid Debugging Workflows

Identifies and patches code errors quickly using native tool integration.

Structured API Responses

Generates valid JSON or schema-compliant outputs for downstream system integration.

Fast Chat Interactions

Delivers low-latency conversational responses for developer-focused assistants.

Not ideal for: Do not use this model for tasks requiring image analysis, audio processing, or outputs longer than 32,768 tokens.

How it compares

Against the peers people actually weigh it against.

Spec	Grok Build	Grok 4.20 Multi-Agent	Grok 4.20
Input /1M	$1.389	$1.688	$1.688
Output /1M	$2.777	$3.375	$3.375
Context	256K	2M	2M
Tools	Yes	No	Yes
Reasoning	Yes	Yes	Yes
Speed	fast	slow	medium

Quick start

Up and running in under two minutes.

1
Create an API key
Sign up and grab a key from the dashboard — $0.50 free credit, no card required.
Get API key →

Make your first request

Drop in your key and send a chat completion — fully OpenAI-compatible.

curl https://kymaapi.com/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-build",
    "messages": [
      {"role": "user", "content": "Explain prompt caching in one paragraph."}
    ]
  }'

Stream responses

Add "stream": true to receive tokens as they arrive.

curl https://kymaapi.com/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-build",
    "stream": true,
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

FAQ

Common questions about this model.

What is the context window of Grok Build?

Grok Build has a 256K-token context window — roughly 376 pages of text in a single request.

How much does the Grok Build API cost?

$1.389 per 1M input tokens and $2.777 per 1M output tokens, with cached input at $0.1389/1M — a 90% discount on repeated prompt prefixes. No subscription; you pay only for what you use.

Does Grok Build support function calling?

Yes — Grok Build supports tool/function calling and structured outputs (JSON mode), so it works with agent frameworks out of the box.

How do I use Grok Build?

Kyma is OpenAI-compatible: point your SDK's base URL at https://kymaapi.com/v1, use your Kyma API key, and set the model to grok-build. Signing up is free and includes $0.50 of credit — no card required.

Does Grok Build support image inputs?

No, it only accepts and generates text. Use a multimodal model if your workflow requires vision.

How does prompt caching affect my costs?

Repeated prompt prefixes are billed at 10% of the standard input rate, reducing costs for stable system prompts or long conversation histories.

What happens if the serving endpoint fails during a request?

Kyma automatically reroutes the request to a healthy serving path, and the response includes the exact cost in usage.cost and the active model in the X-Kyma-Model header.

Start with $0.50 free credit — no card required.Create account →

More models by xAI

Model	Context	Input	Output
Grok 4.5	500K	$2.70	$8.10
Grok 4.3	1M	$1.688	$3.375
Grok 4.20	2M	$1.688	$3.375
Grok 4.20 Multi-Agent	2M	$1.688	$3.375