🚀 Highlights: grok-4.5 is xAI’s newest flagship released on July 8, 2026 (knowledge cutoff February 2026), built for coding and agentic tasks; grok-4.3 and the grok-4.20 series offer a 1M-token context window; the Responses API tools web_search / x_search / code_interpreter / MCP are all verified working on APIYI, and X search is a capability unique to Grok.
Model Lineup
grok-4.5
Flagship · Code & GeneralxAI’s most intelligent model, 500K context, built for coding, agentic tasks, and knowledge work.
grok-4.3
Standard Workhorse1M context at roughly 60% of the flagship price — the balanced choice for everyday chat and mid-level reasoning.
grok-4.20 Variants
Reasoning / Non-Reasoning
-reasoning and -non-reasoning share the same price and 1M context; pick based on whether you want chain-of-thought.grok-build-0.1
Code-Focused256K context and the lowest price in the series — ideal for high-frequency code completion and light coding tasks.
grok-4.20-multi-agent-beta-0309
Multi-Agent CollaborationMultiple agents work in parallel on complex research tasks. Special billing profile — see Multi-Agent Model.
More Capability Pages
Chat/reasoning/vision: Chat & Reasoning; live search: Web & X Search.
Pricing
Listed prices match xAI’s official pricing (verified item-by-item against the APIYI pricing API on 2026-07-13). APIYI’s discount comes from recharge promotions.| Model ID | Context | Input | Output | Positioning |
|---|---|---|---|---|
grok-4.5 | 500K | $2.00 / 1M tokens | $6.00 / 1M tokens | Flagship: code / agents / general |
grok-4.3 | 1M | $1.25 / 1M tokens | $2.50 / 1M tokens | Standard workhorse |
grok-4.20-0309-reasoning | 1M | $1.25 / 1M tokens | $2.50 / 1M tokens | Reasoning variant |
grok-4.20-0309-non-reasoning | 1M | $1.25 / 1M tokens | $2.50 / 1M tokens | Non-reasoning (fast, low-cost) |
grok-4.20-multi-agent-beta-0309 | 1M | $1.25 / 1M tokens | $2.50 / 1M tokens | Multi-agent (billing amplification!) |
grok-build-0.1 | 256K | $1.00 / 1M tokens | $2.00 / 1M tokens | Code-focused |
- The aliases
grok-code-fast/grok-code-fast-1are also callable (connectivity verified); see the model info page for their pricing. - Cached input tokens are billed at a discounted rate. Grok prefix caching is automatic — no configuration needed; see cache billing.
- List prices match xAI official; stack recharge promotions for lower effective cost.
Verified Capability Matrix
Tested on 2026-07-13 (UTC+8) against the APIYI gateway (✅ verified working; — not covered, expected identical on the same architecture):| Capability | grok-4.5 | grok-4.3 | 4.20-reasoning | 4.20-non-reasoning | grok-build-0.1 | multi-agent |
|---|---|---|---|---|---|---|
| Basic chat | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Streaming (with usage) | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
Chain-of-thought reasoning_content | ✅ on by default | ✅ on by default | ✅ | ❌ off by design | ✅ on by default | internal only |
reasoning_effort parameter | ✅ | — | ❌ explicitly rejected | — | — | — |
| Structured Outputs (json_schema) | ✅ | ✅ | ✅ | — | ✅ | ✅ |
| Function calling / Tool Use | ✅ | ✅ | — | — | ✅ | — |
| Vision input (image understanding) | ✅ | ✅ | — | ✅ | — | — |
| Prompt caching (automatic) | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Responses API + server-side tools | ✅ | — | — | — | — | — |
Endpoints
| Endpoint | Method | Purpose |
|---|---|---|
/v1/chat/completions | POST | Chat / reasoning / function calling / structured outputs / vision (shared by all models; select via model) |
/v1/responses | POST | Responses API: web search, X search, code execution, Remote MCP and other server-side tools |
Quick Start
Billing Note: Reasoning Tokens
grok-4.5 / grok-4.3 / grok-build-0.1 reason internally by default: responses include reasoning_content, and reasoning tokens count toward output billing. In testing, a short answer showed just 30 visible tokens but billed 586 output tokens (556 of them reasoning). For cost-sensitive short Q&A, switch to grok-4.20-0309-non-reasoning. Details in Chat & Reasoning.
FAQ
Does Grok have its own native API format?
Does Grok have its own native API format?
No separate proprietary protocol. xAI’s official REST API is OpenAI-compatible:
/v1/chat/completions (chat) plus /v1/responses (Responses API and server-side tools). Point the OpenAI SDK at https://api.apiyi.com/v1 and you get the full feature set — there is no “compatibility-mode downgrade”.How do I enable web search?
How do I enable web search?
Use the Responses API:
tools: [{"type": "web_search"}] (or x_search). The legacy search_parameters field on Chat Completions has been removed by xAI (verified 410) — do not use it. See Web & X Search.The model introduces itself as Grok 4 — is my request hitting the wrong model?
The model introduces itself as Grok 4 — is my request hitting the wrong model?
This is normal. All Grok 4.x models self-identify simply as “Grok 4” (the multi-agent model calls itself Oppie) and won’t report exact version numbers like 4.5 / 4.3. Verify identity via the
model field in your request and the response, not the model’s self-introduction.Does caching need configuration?
Does caching need configuration?
No. Grok prefix caching is automatic; check hits via
usage.prompt_tokens_details.cached_tokens (in testing, the second same-prefix request hit 2688/2735 tokens). The gateway runs in key-pool mode, so set reasonable expectations for hit rates — see cache billing.What happens if I exceed the context window?
What happens if I exceed the context window?
A 400 error. Limits differ per model: grok-4.5 is 500K, grok-4.3 and the 4.20 series are 1M, grok-build-0.1 is 256K. Summarize, chunk, or use RAG retrieval for longer content.
Are failed requests billed?
Are failed requests billed?
4xx client errors (bad parameters / auth failures) are not billed; requests that successfully return tokens are billed by actual usage. Note that
deferred: true is silently ignored — the request actually runs synchronously and is billed normally.Related Docs
Chat & Reasoning
Streaming, chain-of-thought, structured outputs, function calling, vision, caching
Web & X Search
Hands-on with the Responses API web_search / x_search tools
Code Execution & MCP
Server-side Python sandbox and Remote MCP integration
Multi-Agent Model
Capabilities and billing profile of the multi-agent model
Grok 4.5 Launch Deep-Dive
In-depth look at xAI’s newest flagship
Model Info
All available models and groups