Grok 4.5 replaces Grok 4.3 as xAI's coding-focused model, fitting teams running high-volume agentic coding who want low cost per resolved task. It averages 15,954 output tokens per SWE-bench Pro task, well under Claude Opus 4.8's 67,020, at faster output speed than xAI's own prior release.
Released July 8, 2026, Grok 4.5 is xAI's coding and agentic-tool-calling model, trained jointly with Cursor. It scores 54 on the Artificial Analysis Intelligence Index, trailing only Fable 5, GPT-5.5, and Opus 4.8 among frontier models for 4th place overall.
Provider: xAI · Family: Grok 4
Context window: 500,000 tokens
Input modalities: text, image, tool-calls · Output: text, tool-calls
About Grok 4.5
Grok 4.5 is xAI's coding and agentic-workflow model, released July 8, 2026 and trained jointly with Cursor on real developer session data. It is the first numbered Grok release to ship after xAI's all-stock merger into SpaceX, announced in February 2026; the combined entity began trading as SPCX after a June 12, 2026 Nasdaq listing that raised $85.7 billion, the largest IPO on record. Elon Musk described it as "an Opus-class model, but faster, more token-efficient and lower cost," and said xAI's internal assessment placed it roughly comparable to Claude Opus 4.7 on general capability while running much faster. Grok 4.5 sits alongside the larger Grok 4.20 flagship rather than replacing it, targeting coding and tool-calling workloads specifically. On agentic coding benchmarks, Grok 4.5 scored 64.7% on SWE-bench Pro, ahead of GPT-5.5's 58.6% on the same measure but behind Claude Opus 4.8 (69.2%) and Claude Fable 5 (80.4%). It posted 83.3% on Terminal-Bench 2.1 and 29.0% on SWE Marathon, a long-horizon agentic test, and resolved the average coding-agent task using about 15,954 output tokens versus Opus 4.8's 67,020, a gap that compounds into lower real-world cost per task. On Artificial Analysis's cross-vendor Intelligence Index, Grok 4.5 scores 54, ranking 4th among tracked frontier models behind only Claude Fable 5, GPT-5.5, and Claude Opus 4.8. xAI did not publish GPQA Diamond, AIME 2025, MMLU-Pro, or ARC-AGI 2 scores at launch, so its pure academic-reasoning performance versus rivals remains unconfirmed. The context window is 500,000 tokens, half of what Grok 4.3 supported and a quarter of Grok 4.20's multi-agent variant, a deliberate tradeoff xAI made for lower cost and latency rather than a defect. xAI has not disclosed Grok 4.5's parameter count or confirmed whether it uses a dense or mixture-of-experts architecture, a departure from the detailed design claims made around Grok 4.20. Reasoning effort is configurable across low, medium, and high depths, defaulting to high, and xAI's documentation recommends context compaction, meaning periodic summarization of older tool-call history, to work within the smaller window on long agent sessions. Grok 4.5 accepts text and image input and returns text only, with no confirmed audio or video input or output. Tool use ships natively rather than through third-party integrations, covering most of what an agentic coding pipeline needs out of the box (see Key Features below for the full list). Pricing sits well under Claude Opus 4.8's list rate and undercuts xAI's own Grok 4.20 flagship, the core of xAI's pitch to teams running constant, high-volume agent workloads (exact tiers are in the pricing section below). Grok 4.5 is reachable through the xAI API (Responses API and Chat Completions), the Grok Build terminal coding agent (itself Apache 2.0 licensed, though that license covers only the agent runtime, not the model weights), Cursor on all plans, Microsoft Office add-ins, and gateways including OpenRouter, Vercel AI Gateway, Cloudflare Workers AI, Snowflake Cortex, and Databricks Mosaic AI. At launch it was not yet available in the EU API console, with xAI stating wider regional availability was expected later the same month. The model is closed-weight and proprietary, and xAI had not published a dedicated system card or model card for Grok 4.5 as of this writing, unlike Grok 4, Grok 4 Fast, Grok 4.1, and Grok 4.20, each of which shipped a PDF model card at data.x.ai. That gap matters against the Grok product line's recent record: a Common Sense Media report on child-safety testing, covered by TechCrunch in January 2026 under the headline "among the worst we've seen," flagged serious failures across Grok's consumer products, and a separate Anti-Defamation League study scored Grok worst of six major chatbots on antisemitic-content detection, at 21 out of 100 versus Claude's 80. Neither finding is specific to Grok 4.5's own testing, since both predate this release, but buyers evaluating it for consumer-facing or minor-accessible products should treat the missing system card as an open question rather than an oversight to ignore. Grok 4.5 fits teams that want a cheaper, faster coding assistant inside Cursor or a terminal agent loop and do not need the largest available context window or a fully documented benchmark sheet. Teams doing long-document analysis, large-codebase work above its context budget, or anything requiring a current, published safety card are better served by Grok 4.20, Claude Opus 4.8, or GPT-5.5 until xAI publishes fuller documentation for this specific release.
Pricing
Standard tier: $2.00 per 1M input tokens, $6.00 per 1M output, $0.50 per 1M cached input, for prompts up to 200,000 tokens. Extended tier applies above that threshold: $4.00 input, $12.00 output, $1.00 cached per 1M tokens. No batch or provisioned-throughput discount is published for this release.
Key Features
- Tiered Pricing by Prompt Size: A standard per-token rate applies below a set prompt-size threshold; cross it and the rate roughly doubles for that same request.
- Three Reasoning Depths: Toggle low, medium, or high reasoning per request; defaults to high for agentic coding accuracy.
- Native Tool and Code Execution: Built-in function calling, structured JSON output, web search, X search, and code execution need no extra orchestration layer.
- 75% Cached-Input Discount: Cached input tokens in the standard tier cost a quarter of fresh input pricing, rewarding agent loops that reuse system prompts.
- Cursor and Grok Build Integration: Trained jointly with Cursor and live same-day in Cursor on all plans, Grok Build, and Microsoft Office add-ins.
Pros
- Costs about $0.31 per task on the Artificial Analysis Intelligence Index evaluation, over 60% cheaper than Opus 4.8 or GPT-5.5 for comparable work.
- Beats GPT-5.5 head-to-head on SWE-bench Pro, the one coding benchmark xAI chose to publish at launch.
- Live at launch across Cursor, Grok Build, Office add-ins, and five model gateways with no waitlist, unlike xAI's historically staggered rollouts.
Cons
- No Grok 4.5-specific system card or safety documentation published at launch, a real gap given the Grok product line's documented child-safety and content-moderation controversies.
- Context window shrank from the prior release, a regression for teams with long-context workflows already built on Grok 4.3.
- Parameter count and architecture (dense vs mixture-of-experts) remain undisclosed, unlike more transparent rivals.
Benchmarks
- swe marathon: 29
- swe bench pro: 64.7
- terminal bench 2 1: 83.3
- avg output tokens per task: 15954
- artificial analysis coding index: 76
- artificial analysis intelligence index: 54
- artificial analysis speed tokens per sec: 89.5
Frequently Asked Questions
How much does Grok 4.5 cost in 2026?
Grok 4.5 costs $2.00 per 1 million input tokens and $6.00 per 1 million output tokens for prompts up to 200,000 tokens, with cached input billed at $0.50 per 1 million, a 75% discount. Prompts longer than 200,000 tokens shift to an extended tier at $4.00 input, $12.00 output, and $1.00 cached per 1 million tokens. There is no published batch or provisioned-throughput discount for this release. A daily coding agent processing roughly 1 million input and 200,000 output tokens costs about $3.20 at list price before caching savings.
Is Grok 4.5 free to use?
No, Grok 4.5 has no free tier; access runs entirely on paid, per-token API pricing through xAI or a gateway like OpenRouter. Teams wanting to evaluate it without commitment can try it inside Cursor, which offers its own free plan with limited model credits, or through Grok Build's CLI on a pay-as-you-go API key. There is no trial credit or capped free quota published directly by xAI for this model.
What are the best alternatives to Grok 4.5?
GPT-5.5 is the closest direct rival on price and positioning, though it trails on SWE-bench Pro. Claude Opus 4.8 leads on raw coding accuracy and is the pick when peak resolve rate matters more than cost per task. xAI's own Grok 4.20 offers a much larger context window for teams doing large-codebase or long-document work that will not fit inside Grok 4.5's smaller budget.
How does Grok 4.5 compare to GPT-5.5 in 2026?
Grok 4.5 scores 64.7% on SWE-bench Pro versus GPT-5.5's 58.6% on the same benchmark, xAI's one published head-to-head coding comparison at launch. It also resolves the average coding task using far fewer output tokens than typical for models in this class, which lowers real-world cost per task beyond the sticker price. Neither vendor published GPQA Diamond, AIME, or MMLU-Pro scores for these specific releases, so the pure-reasoning gap between them is unconfirmed. Pick Grok 4.5 for cheaper, faster coding-agent throughput; pick GPT-5.5 if you need a wider-documented benchmark suite for procurement.
How do you get started with Grok 4.5?
Sign up for an xAI API key at docs.x.ai and call the Responses API or Chat Completions endpoint with model name grok-4.5; no waitlist was required at launch. Cursor users can select Grok 4.5 directly from the model picker on any paid plan without separate API setup. For a fully agentic coding workflow, xAI's own Grok Build CLI (Apache 2.0 licensed) runs Grok 4.5 against a local repository using the same API key. Budget for the standard per-token rate and enable prompt caching early, since repeat system prompts qualify for the 75% cached-input discount from the first request.
Top Alternatives
- GPT-5.5: Pick Grok 4.5 if you want higher SWE-bench Pro accuracy at a similar price; pick GPT-5.5 for a wider-documented benchmark suite.
- Claude Opus 4.8: Pick Grok 4.5 if per-task cost matters most; pick Opus 4.8 if you need the single highest coding accuracy regardless of price.
- Grok 4.3: Pick Grok 4.3 if you need its larger context window; pick Grok 4.5 for lower cost per resolved coding task.
- Grok 4.20: Pick Grok 4.20 if you need a larger context window or a published system card; pick Grok 4.5 for cheaper, faster coding-agent throughput.