by xAI · Grok 4 family · best for real-time research and agentic work at frontier-class value
Grok 4.3 is xAI's current flagship model, released to the public API on 2026-04-30 (beta on grok.com 2026-04-17). It is a reasoning-first, natively multimodal model — text, image, and native video input — with a 1,000,000-token context window and xAI's signature live access to the X (Twitter) corpus. The single sentence a buyer needs: it delivers frontier-class reasoning and the best real-time-data capability on the market at a price (just $1.25 in / $2.50 out per 1M tokens) that undercuts every comparable flagship by a wide margin — with the trade-off of slow first-token latency and unusually thin published benchmarks. Provider: xAI. Released: 2026-04-30. Status: GA. Context: 1M tokens. Max output: undisclosed. Modalities: text + image + video in, text out. Knowledge cutoff: December 2025. Headline price: $1.25 / $2.50 per 1M tokens.
| Benchmark | Score | Source |
|---|---|---|
| IFEval | 81% | Artificial Analysis (IFBench, held flat vs 4.20)2026-04-30T00:00:00.000Z |
| TAU-bench | 98% | Artificial Analysis (tau-2-Bench Telecom)2026-04-30T00:00:00.000Z |
| GPQA Diamond | 90% | Artificial Analysis / xAI launch coverage (approximate)2026-04-30T00:00:00.000Z |
| Artificial Analysis Index | 53 | artificialanalysis.ai 2026-05-28T00:00:00.000Z |
Six personas, six verdicts — the same panel that reviews every product on TopReviewed.
“Frontier reasoning at a fifth of Opus pricing, with a live-data moat — but I'm buying it as a second vendor, not my safety-critical default.”
For a buyer, Grok 4.3 is the clearest value play among flagships: frontier-band reasoning, a genuine real-time-data moat, and Azure AI Foundry availability that adds enterprise controls xAI's own API lacks. The vendor risk is real — thin benchmark disclosure, no published safety framework, no verified compliance certs, and a moderation posture shaped by public controversy. OpenAI/Anthropic-SDK compatibility keeps lock-in low, so it slots cleanly as a cost-optimized or research-focused second vendor. Roadmap confidence is moderate: xAI ships fast (four flagships in a year) but reprices and retires slugs aggressively, which raises operational churn.
“Grok's moat isn't the benchmark — it's the X firehose and the Musk-ecosystem distribution that no rival can clone.”
In market terms, Grok 4.3's defensibility comes from data and distribution, not raw IQ. Native access to the live X corpus is a moat Anthropic, OpenAI, and Google cannot replicate without owning a social graph, and the Tesla / SpaceX / X ecosystem gives xAI built-in surfaces (in-car assistant, X Premium, grok.com) that competitors must win through partnerships. The "edgier" positioning differentiates against the homogeneously-corporate voices of ChatGPT and Claude. Market timing is strong: shipping the cheapest frontier flagship during a price war pressures rivals directly. The weakness is that the ecosystem narrative (Tesla, SpaceX) is still more story than shipped product outside X itself.
“At $1.25 in / $2.50 out with 84% cache reads, this is frontier reasoning at clearance pricing — just watch the long-context double-rate.”
The unit economics are excellent. Grok 4.3 undercuts Claude Opus 4.7 by roughly 5–10x on token price and beats GPT-5.5 by a wide margin while sitting in the frontier reasoning band on the AA Index. The 84% cached-input discount makes iterative and agentic workloads cheap. Two cost traps to model: the long-context tier doubles input/output above 200K tokens, which can quietly inflate large-document bills, and always-on reasoning produces ~44% more output tokens than Grok 4.20, inflating per-call output cost. For batch, cached, and well-scoped workloads, value-per-dollar is best-in-class; for ad-hoc long-doc work, model the bill carefully.
“OpenAI/Anthropic-SDK compatible, clean function calling, one-line X search — but budget for ~20s first tokens and thinner docs.”
For builders, adoption is frictionless: drop-in OpenAI- or Anthropic-SDK compatibility, working structured outputs, parallel tool calls, and the standout X-search tool that pulls live posts into a prompt with one call. The 1M window removes a lot of RAG plumbing. The friction is real: ~19.7s time-to-first-token feels slow in interactive loops, the SDK/docs ecosystem still trails OpenAI and Anthropic in polish and examples, and reasoning visibility is summary-only. Coding-agent work is better served elsewhere given the soft coding profile. Reliability is decent but rate limits are spend-tiered rather than transparently fixed.
“It actually has opinions and knows what happened this morning — but you wait for the first token and the guardrails feel inconsistent.”
For a heavy daily user, Grok via grok.com / X Premium feels distinct from ChatGPT or Claude: looser personality, readier opinions, and willingness to engage with topics other assistants deflect. The live-X integration makes it the natural choice for current-events and trend questions. Downsides are well known: long TTFT feels sluggish next to GPT-5.5 or Gemini 3.1, output quality occasionally suffers from the loose guardrails, the consumer tier maze (X Premium $8, SuperGrok Lite $10, SuperGrok $30, X Premium+ $40, Heavy $300) is confusing, and image/NSFW moderation is now aggressive and inconsistent. For users who already live on X, bundled access is strong value.
“No SWE-bench number, no architecture, no safety framework — a 53 Intelligence Index and a firehose don't make a frontier leader.”
Adversarially, Grok 4.3's marketing outpaces its disclosure. The conspicuously-absent SWE-bench Verified figure reads as an omission of a weak result; independent coverage confirms it trails Opus 4.7 by double digits on hard coding. The AA Index of 53 is good-not-leading, below GPT-5.5 and Gemini 3.1 Pro. Architecture is undisclosed, there is no published safety framework, no verified compliance, and AA-Omniscience non-hallucination dropped 8 points versus 4.20. The real-time-data moat is genuine and the price is genuinely excellent — those claims hold. But "fastest, most intelligent model we've built" is vendor framing the standalone benchmarks don't fully substantiate, and the moderation history (Jan 2026 imagery scandal) is a live reputational risk.
The full research notes behind this review — verified against primary sources.
xAI discloses almost nothing about Grok 4.3's internals. Architecture type, parameter counts, attention mechanism, layer counts, training tokens, and compute are all undisclosed — honestly null here. The model is widely assumed to be a mixture-of-experts design trained on xAI's Colossus / Memphis compute, but this is not confirmed by any xAI model card, so it is marked unknown. What is documented: a 1M-token input context, always-on chain-of-thought reasoning with selectable effort (low / medium / high), native multimodal ingestion including video, and a December 2025 knowledge cutoff. Compared with Anthropic, OpenAI, and Google — all of whom publish at least partial architecture and benchmark detail — xAI's transparency is materially thinner, which is the single biggest caveat on this entry.
| Benchmark | Score | vs Predecessor | vs Top Competitor | Source |
|---|---|---|---|---|
| Artificial Analysis Intelligence Index | 53 | +4 vs Grok 4.20 (49) | Below GPT-5.5 (~60), Gemini 3.1 Pro (~57); ahead of Claude Sonnet 4.6 | Artificial Analysis |
| GPQA Diamond | ~90% | Up from ~78.5% (Grok 4.20) | Near GPT-5.5 / Gemini 3.1 Pro band | AA / launch coverage |
| GDPval-AA (tool-use Elo) | 1500 | +321 vs Grok 4.20 (1179) | Among highest agentic Elos measured | AA launch article |
| tau-2-Bench Telecom | 98% | +5 vs Grok 4.20 | Top-tier | AA launch article |
| IFBench | 81% | Flat vs Grok 4.20 | Competitive | AA launch article |
(MMLU-Pro, AIME 2025, MATH-500, SWE-bench Verified, HumanEval, LiveCodeBench, Aider Polyglot, MMMU, and a clean Grok 4.3 LMArena text Elo were not published by xAI's model card or available from third-party leaderboards as standalone, verifiable figures at verification time. Rows left null rather than invented. xAI publishes materially less benchmark detail than Anthropic, OpenAI, or Google.)
Output throughput is strong — Artificial Analysis measures ~181.5 tokens/sec at high reasoning (top-10 among tracked models). The catch is time-to-first-token: ~19.7 seconds, because reasoning is always on and cannot be disabled, only dialed down. This makes Grok 4.3 a poor fit for sub-second interactive UX but fine for research, batch-style, and agentic workloads where total quality matters more than first-token latency. The model is also verbose — it used ~88M output tokens to complete the AA Intelligence Index suite (about 44% more than Grok 4.20), which inflates per-call output cost.
| Surface | Cost | Notes |
|---|---|---|
| API input | $1.25 / 1M tok | Doubles above 200K input tokens (long-context tier) |
| API output | $2.50 / 1M tok | Always-on reasoning makes outputs verbose |
| Cached input | $0.20 / 1M tok | 84% discount (cache read) |
| Batch | n/a | No documented batch endpoint |
| Image input | token-converted | No published per-image price |
| Direct UI (SuperGrok) | $30 / mo | Standalone Grok subscription, no X perks |
| Direct UI (SuperGrok Lite) | $10 / mo | Light tier, Grok Imagine access |
| Direct UI (X Premium / Premium+) | $8 / $40 mo | Bundled Grok inside the X app; Premium+ adds higher limits + ad-free X |
| SuperGrok Heavy | $300 / mo | Power-user / heavy-reasoning tier |
| Free tier | $0 | grok.com + free X tier with daily caps |
| Rate limits | tiered by spend/plan | Per docs.x.ai |
Pricing-conflict note (carried from v1, now resolved): Artificial Analysis still lists the Grok 4.x line under older figures in places, and third-party trackers vary. xAI's docs.x.ai card is canonical: $1.25 in / $2.50 out / $0.20 cached. Where OpenRouter or aggregators disagree, defer to docs.x.ai.
Proprietary, API-only, no open weights and not self-hostable. The x.ai endpoint is OpenAI-SDK and Anthropic-SDK compatible, which keeps switching cost low. Managed cloud availability is now real: Microsoft Foundry / Azure AI Foundry hosts Grok 4.3 with enterprise controls (RBAC, private networking, customer-managed keys) — but note the Azure deployment caps context at ~200K tokens versus 1M on the direct x.ai API. OpenRouter resells the model. No Bedrock or Vertex availability. Rate limits are tiered by spend/plan rather than a fixed default RPM/TPM.
xAI has no published Responsible-Scaling-Policy equivalent; governance rests on an Acceptable Use Policy. Two honest points for enterprise buyers:
trains_on_inputs: true with data_optout_available: false to reflect the stricter, consumer-facing reality.SDKs in Python and TypeScript, plus OpenAI-SDK and Anthropic-SDK drop-in compatibility. Framework integrations include LangChain and the Vercel AI SDK; OpenRouter resells it; Azure AI Foundry hosts it. Notable surfaces: Grok inside X, grok.com, the SuperGrok subscriptions, and the Tesla in-car assistant. Popularity is growing rather than dominant — strong among X-native and developer audiences, less penetrated in conservative enterprise.
$1.25 per 1M input tokens and $2.50 per 1M output tokens, with cached input at $0.20 (84% off). Above 200K input tokens, rates double. Consumer access starts at X Premium $8/mo or SuperGrok $30/mo.
It is the weakest area. xAI did not publish a SWE-bench Verified score for 4.3, and it trails Claude Opus 4.7 by double digits on hard agentic coding. For a coding agent, prefer Grok Build 0.1 within xAI or Claude/Codex elsewhere.
Native, first-party access to the live X (Twitter) firehose plus web search, and native video input — neither of which competing flagships offer natively.
Yes, via Microsoft Foundry / Azure AI Foundry (RBAC, private networking, customer-managed keys), though Azure caps context at ~200K tokens versus 1M on the direct API.
On the API, only if you opt into data sharing (irreversible once enabled). On the X consumer surface, the 2026 ToS trains on prompts/outputs by default with no opt-out.
Reasoning is always on (effort dial only, no off switch), so time-to-first-token is ~20s. It is built for quality, not interactive latency.
Retired slugs (grok-3, grok-4-0709, the fast pairs) auto-redirect to Grok 4.3 and bill at 4.3 pricing; reasoning maps to low effort, non-reasoning to none.
Wins decisively on hard coding (SWE-bench ~87.6% vs Grok's unpublished/weak), reasoning ceiling, and published safety; loses on price (5–10x more) and has no real-time data access.
Higher AA Intelligence Index (~60) and far broader benchmark transparency; loses on price and on native real-time data.
Higher AA Index (~57), stronger multimodal breadth, comparable-to-larger context; loses on real-time X access and on token price.
Primary references used to verify this review.
Last verified 2026-05-27