What is the Grok 4.5 API and where can I use it?

The Grok 4.5 API is xAI's flagship reasoning model, launched 2026-07-08 and available today on Emix.ai. Call it at `POST https://api.emix.ai/grok/v1/responses` with Bearer token auth in the Responses API format. Full request and response schema lives at `https://docs.emix.ai`.

How do I get Grok 4.5 API access?

Sign up on Emix.ai, claim your free credits, and generate an `EMIX_API_KEY` from the dashboard. The same key works for `grok-4-5` and every other model in the Emix.ai catalog. Start in the Playground at `https://emix.ai/grok-4-5`, then move to the API when the request shape is stable.

What are the Grok 4.5 API parameters on Emix.ai?

`model: "grok-4-5"`, an `input` array of messages with text and/or image/file parts, `reasoning.effort` (`low` / `medium` / `high` / `xhigh`, default `low`), `tools` (including the built-in `web_search`), `response_format` for structured JSON output, and `stream`. There is no `max_tokens` parameter. Full schema: `https://docs.emix.ai`.

How does the Grok 4.5 API compare to the Grok 4.3 API?

Grok 4.5 adds a four-level `reasoning.effort` control (`low` → `xhigh`), a built-in `web_search` tool, first-class Structured Output plus function calling with parallel tool calls, and moves to the Responses API endpoint at `/grok/v1/responses`. Migrating: swap the model ID, move to the Responses endpoint, and remove `max_tokens`.

What can I build with the Grok 4.5 API?

Research agents with live web grounding, coding copilots and PR review bots, vision-grounded document analytics, tool-using support agents, high-volume reasoning workloads at `reasoning.effort: low`, and multimodal in-product assistants that combine screenshots with typed tool calls.

What is the Grok 4.5 API pricing on Emix.ai?

Grok 4.5 is billed per million tokens in credits (1 credit = $0.005), with separate rates for input, cached input and output, and a bonus on high-tier credit top-ups. See the pricing card on this page and `https://emix.ai/pricing` for the live table, and `https://docs.emix.ai` for how caching is applied to your requests.

Are there free credits for the Grok 4.5 API?

Yes. New Emix.ai accounts get free credits at signup that are usable immediately against `grok-4-5` and every other model in the Emix.ai catalog.

Does the Grok 4.5 API support vision, tools and web search?

Yes to all three. The model accepts interleaved text plus image and file uploads, supports function calling with parallel tool calls, and ships a built-in `web_search` tool you enable per request by adding `{"type": "web_search"}` to the `tools` array.

Does the Grok 4.5 API expose reasoning traces or a `max_tokens` parameter?

No. Grok 4.5 reasons internally and returns clean final answers — the visible chain-of-thought is not streamed. The request also does not accept a `max_tokens` parameter; control depth via `reasoning.effort` instead.

What is the Grok 4.5 API context window?

xAI has not publicly confirmed a specific context length for Grok 4.5. Check `https://docs.emix.ai` for the current limits on the Emix.ai endpoint.

How do I test the Grok 4.5 API for free before integrating?

Try `grok-4-5` directly on `https://emix.ai/grok-4-5`, then move to the Emix.ai Playground to iterate on `reasoning.effort`, tool use and Structured Output against your real prompts before you write any code.

README.md

Grok 4.5 API on Emix.ai: Opus-Class Reasoning, Vision Input, Tools and a Built-in Web Search

The Grok 4.5 API is live on Emix.ai. It's an Opus-class reasoning model with per-request reasoning effort (low / medium / high / xhigh), text + image/file input, Structured Output, function calling, streaming, and a built-in web_search tool. Call it at POST https://api.emix.ai/grok/v1/responses in the Responses API format with Bearer token auth. Free credits at signup — see the pricing card for rates.Grok 4.5 is xAI's flagship reasoning model, launched on 2026-07-08, and available today on Emix.ai through one unified endpoint. This page covers what the Grok 4.5 API does, the real parameters on Emix.ai, how it compares to the Grok 4.3 API, and how to send your first request in under a minute.

Try Grok 4.5 in Playground Read the Docs

Key Capabilities of Grok 4.5 API on Emix.ai

The Grok 4.5 API is an Opus-class reasoning model with native multimodal input, first-class tool use, and per-request control over how hard it thinks. Every capability below is live in production on api.emix.ai.

Per-request reasoning effort with four levels

Grok 4.5 exposes a reasoning.effort parameter with four discrete levels — low, medium, high, and xhigh — defaulting to low. Ratchet effort up for hard math, multi-step code review and multi-hop research where accuracy pays for the extra tokens; keep it low for chat-speed responses and high-volume classification. Depth is a request-level knob, not a model-variant choice, so the same grok-4-5 model ID serves your fast path and your deep-reasoning path. The visible chain-of-thought is not streamed — the model reasons internally and returns clean final answers.

Native text + vision multimodal input

The Grok 4.5 API accepts text alongside image and file uploads interleaved in the same request. Use it for chart reading, UI understanding, invoice and document parsing, diagram QA and visual grounding for agent workflows. Output is text — including strictly structured JSON when you constrain the response — which keeps downstream parsing deterministic even when the input is a screenshot or a scanned page. Vision is not a separate endpoint or add-on; it's the same call.

Structured Output and function calling in one request

Structured Output and function-calling tools are both first-class and can be combined in a single call. Constrain responses to a JSON schema for deterministic downstream parsing, hand Grok 4.5 a set of typed tool definitions, and let it plan, call and compose — including parallel tool calls when steps are independent. These are the primitives for real agent workflows: the model decides which tool to invoke, your runtime executes it, and the final answer comes back in the shape your frontend expects.

Built-in `web_search` tool for live grounding

Grok 4.5 ships with a first-party web_search tool built into the API — enable it per request to give the model live web access for questions about current events, prices, documentation and public information. No separate retrieval stack, no external search API to wire in, no vector store to maintain for freshness. Combine web_search with reasoning.effort: high and Structured Output and you have the shape of a research agent in a single POST.

What Can You Build with the Grok 4.5 API

Six patterns developers are shipping against the Grok 4.5 API on Emix.ai today.

Research agents with live web grounding

Combine reasoning.effort: high with the built-in web_search tool to build agents that read live sources, cross-reference them, and produce cited briefs — no separate search API to wire in.

Coding copilots and repo-scale review

Strong code reasoning plus function calling make Grok 4.5 a fit for PR review bots, refactor planners and migration assistants. Bump effort to xhigh on hard reviews and stream the diff back.

Vision-grounded document analytics

Send screenshots of dashboards, invoices or scanned PDFs and receive structured JSON via the Structured Output mode. Good for finance ops, RPA and internal analytics tools.

Tool-using customer support agents

Wire the Grok 4.5 API into your CRM and knowledge base via function calling. The model plans, retrieves, drafts and escalates, with typed outputs your frontend can render deterministically.

High-volume reasoning workloads

For classification, extraction and moderation at scale, pin reasoning.effort: low and lean on cached prompt input for repeated system prompts and context. You get reasoning-quality outputs without dropping to a non-reasoning model.

Multimodal assistants

Pair text-and-image input with Structured Output to build product assistants that can "look at this screen and act" — visual QA, guided troubleshooting, and in-product help flows.

Grok 4.5 API Parameters on Emix.ai

Real, confirmed surface from the live Emix.ai model config. Everything below is what you'll actually see when calling POST https://api.emix.ai/grok/v1/responses.

Parameter	Value	Notes
Endpoint	POST https://api.emix.ai/grok/v1/responses	Responses API format
Auth	Authorization: Bearer $EMIX_API_KEY	Standard bearer token
model	grok-4-5	Canonical model ID on Emix.ai
Modalities in	text, image, file upload	Interleaved in a single request
Modalities out	text (including structured JSON)	Visible chain-of-thought not exposed
reasoning.effort	low / medium / high / xhigh	Default: low
Structured Output	supported	JSON-schema-constrained responses
Function calling / tools	supported	Includes parallel tool calls
Built-in tools	web_search	Live web grounding
Streaming	supported (SSE)	Set stream: true
max_tokens	not supported	No max-tokens knob on the request
Context window	see docs.emix.ai	Not publicly confirmed by xAI

Grok 4.5 API vs Grok 4.3 API

Grok 4.5 is a meaningful step up from the Grok 4.3 API on the surface area that actually matters in production. If you're already on the Grok 4.3 API through Emix.ai, migration is: swap model to grok-4-5, move to the /grok/v1/responses endpoint, drop max_tokens, and add reasoning.effort where you want the depth.

	Grok 4.5 API	Grok 4.3 API
Reasoning depth control	Four `reasoning.effort` levels (`low` → `xhigh`), chosen per call	Fixed variant — no per-request depth knob
Built-in web_search tool	First-class built-in `web_search` tool — no separate retrieval stack	Not built in — bring your own retrieval
Structured Output + function calling	Both first-class in the same request, including parallel tool calls	Available but not combined as first-class primitives
Endpoint / request shape	Responses API at `POST https://api.emix.ai/grok/v1/responses`	Chat-completions surface — small request-shape change on migration
max_tokens parameter	Not supported — remove from payload	Accepted on the request

Quick Start: Send Your First Grok 4.5 API Request

Four steps from zero to a working call on Emix.ai.

Online Test

Open the Grok 4.5 model page at https://emix.ai/grok-4-5 and try it directly in the browser with your own prompts and images — no key required.

Playground

Open the Emix.ai Playground, pick grok-4-5, and dial reasoning.effort between low, medium, high and xhigh to feel the quality/latency tradeoff on your real inputs. Toggle the built-in web_search tool and Structured Output to prototype the exact request shape you need.

Get API Access

Sign up on Emix.ai, claim your free credits, and create an EMIX_API_KEY from the dashboard. The same key works across every model in the Emix.ai catalog.

Send Your First Request

bash

curl https://api.emix.ai/grok/v1/responses \
  -H "Authorization: Bearer $EMIX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4-5",
    "input": [
      {"role": "user", "content": "Summarize this repo and propose 3 refactors."}
    ],
    "reasoning": {"effort": "high"},
    "tools": [{"type": "web_search"}],
    "response_format": {"type": "json_object"},
    "stream": true
  }'

Full request and response schemas live at https://docs.emix.ai.

Why Choose Emix.ai for the Grok 4.5 API

Live now with free credits

Grok 4.5 is available today on Emix.ai. New accounts get free credits usable immediately against grok-4-5.

One API for the entire Grok series and beyond

Call Grok 4.5, Grok 4.3, Grok Imagine Video 1.5 and the rest of the Emix.ai catalog — Claude Opus 4.8, Claude Sonnet 5, GPT-5.5, Gemini 3.5 Flash and more — through a single account and one billing surface.

Transparent, credit-based pricing

See the pricing card for the current rates on input, cached input and output tokens. No reasoning surcharges hidden in the fine print.

Cached input at a flat discount

Prompt caching is billed at a flat discount versus fresh input — real savings on long system prompts and repeated context. Rates on the pricing card.

First-party tools built in

Grok 4.5's web_search tool works out of the box — no separate retrieval stack to configure.

Developer support that actually answers

Direct Slack/Discord access to engineers who use these models daily, plus first-party guides for tool use, Structured Output and the Responses API shape.

Grok 4.5 API Availability

Status, release and migration at a glance

- **Status:** Live on Emix.ai
- **Released:** 2026-07-08 by xAI
- **Endpoint:** POST https://api.emix.ai/grok/v1/responses
- **Docs:** https://docs.emix.ai
- **Free credits:** Yes, at signup
- **Migration from Grok 4.3:** Swap model to grok-4-5, move to the Responses endpoint, drop max_tokens, optionally add reasoning.effort

Developer feedback on the Grok 4.5 API

Launch-window developer feedback across the Emix.ai Grok series.

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