Choose Anthropic: Claude Opus 5.5 if…
- you want the newer model — released 2026-09-22, 5 months after the other
Anthropic: Claude Opus 5.5 vs SpaceXAI: Grok 4.3 (batch)
Neither wins outright: Anthropic: Claude Opus 5.5 is the pick when you want the newer model, SpaceXAI: Grok 4.3 (batch) when cost matters at scale.
Key numbers
| Spec | Anthropic: Claude Opus 5.5 | SpaceXAI: Grok 4.3 (batch) |
|---|---|---|
| Provider | Anthropic | X Ai |
| Input price (per 1M tokens) | $4.00 | $1.00 |
| Output price (per 1M tokens) | $20.00 | $2.00 |
| Blended price (3:1 input/output) | $8.00 | $1.25 |
| Cheaper than … of all models we track | 7% | 35% |
| Context window | 1M tokens (~1,500 pages) | 1M tokens (~1,500 pages) |
| Larger context than … of all models | 69% | 69% |
| Max output per response | 128K tokens (~96,000 words) | 900K tokens (~675,000 words) |
| Input types | text, image, file | text, image, file |
| Output types | text | text |
| Free variant | No | No |
| Listed since | 2026-09-22 | 2026-04-30 |
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What it costs for real workloads
Monthly cost at list price for five common workloads. Token counts per unit are stated so you can scale them to your own traffic. A workload that does not fit a model's context window is marked rather than priced.
| Workload (per month) | Anthropic: Claude Opus 5.5 | SpaceXAI: Grok 4.3 (batch) | Difference |
|---|---|---|---|
| Customer-support chatbot 50,000 conversations — each a 6-turn conversation (1,500 in / 400 out tokens) | $700 | $115 | SpaceXAI: Grok 4.3 (batch) saves $585 |
| RAG search over documents 20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens) | $680 | $140 | SpaceXAI: Grok 4.3 (batch) saves $540 |
| Coding / tool-using agent 2,000 tasks — each a multi-step task with tool calls and file context (60,000 in / 6,000 out tokens) | $720 | $144 | SpaceXAI: Grok 4.3 (batch) saves $576 |
| Batch summarisation 10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens) | $440 | $92.00 | SpaceXAI: Grok 4.3 (batch) saves $348 |
| Long-document analysis 500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens) | $220 | $52.00 | SpaceXAI: Grok 4.3 (batch) saves $168 |
Capabilities side by side
| Capability | Anthropic: Claude Opus 5.5 | SpaceXAI: Grok 4.3 (batch) | What it lets you do |
|---|---|---|---|
| Tool / function calling | ✓ Yes | ✓ Yes | call your APIs and run agent loops |
| Structured output (JSON schema) | ✓ Yes | ✓ Yes | return JSON that validates against your schema |
| Reasoning / thinking mode | ✓ Yes | ✓ Yes | spend extra tokens thinking before answering hard problems |
| Image input | ✓ Yes | ✓ Yes | read screenshots, charts and scanned pages |
| Audio input | — | — | take speech or audio directly |
| File / PDF input | ✓ Yes | ✓ Yes | accept documents without your own parsing step |
| Image output | — | — | generate images, not just text |
| Built-in web search | ✓ Yes | ✓ Yes | answer from live web results |
| Seed (reproducible sampling) | — | ✓ Yes | repeat a generation for tests and evals |
| Log-probabilities | — | ✓ Yes | read token confidence for classification and scoring |
From each model's published parameters and input/output types. “—” means not advertised, not proven absent.
Price history
- Anthropic: Claude Opus 5.5: price unchanged since we started tracking it on 2026-09-23.
- SpaceXAI: Grok 4.3 (batch): price unchanged since we started tracking it on 2026-09-04.
Which should you choose?
Choose SpaceXAI: Grok 4.3 (batch) if…
- cost matters at scale — it is 84% cheaper on a typical 3:1 input/output mix ($115 vs $700 a month for 50,000 support chats)
- you need seed (reproducible sampling) — to repeat a generation for tests and evals; Anthropic: Claude Opus 5.5 does not advertise it
- you need log-probabilities — to read token confidence for classification and scoring; Anthropic: Claude Opus 5.5 does not advertise it
- you generate long outputs in one go — up to 900K tokens (about 675,000 words) per response
Frequently asked questions
Is Anthropic: Claude Opus 5.5 better than SpaceXAI: Grok 4.3 (batch)?
Neither wins outright: Anthropic: Claude Opus 5.5 is the pick when you want the newer model, SpaceXAI: Grok 4.3 (batch) when cost matters at scale. In short: Anthropic: Claude Opus 5.5 when you want the newer model; SpaceXAI: Grok 4.3 (batch) when cost matters at scale, you need seed (reproducible sampling), you need log-probabilities, you generate long outputs in one go.
Which is cheaper, Anthropic: Claude Opus 5.5 or SpaceXAI: Grok 4.3 (batch)?
SpaceXAI: Grok 4.3 (batch) is cheaper: $1.25 vs $8.00 per 1M tokens at a typical 3:1 input/output mix, 84% less. For 50,000 support conversations a month that is $115 against $700.
How much do Anthropic: Claude Opus 5.5 and SpaceXAI: Grok 4.3 (batch) cost per million tokens?
Anthropic: Claude Opus 5.5 costs $4.00 per 1M input tokens and $20.00 per 1M output tokens; SpaceXAI: Grok 4.3 (batch) costs $1.00 input and $2.00 output. Output tokens are billed separately, so long answers shift the gap.
Which has the bigger context window, Anthropic: Claude Opus 5.5 or SpaceXAI: Grok 4.3 (batch)?
Both take 1M tokens per request — roughly 1,500 pages of text.
Do Anthropic: Claude Opus 5.5 and SpaceXAI: Grok 4.3 (batch) support function calling and JSON output?
Tool calling — Anthropic: Claude Opus 5.5: yes, SpaceXAI: Grok 4.3 (batch): yes. JSON-schema structured output — Anthropic: Claude Opus 5.5: yes, SpaceXAI: Grok 4.3 (batch): yes.
Can Anthropic: Claude Opus 5.5 or SpaceXAI: Grok 4.3 (batch) read images?
Yes, both accept image input.
Is Anthropic: Claude Opus 5.5 or SpaceXAI: Grok 4.3 (batch) free to use?
No free variant is listed for either; both are pay-per-token.
What is the maximum output length of Anthropic: Claude Opus 5.5 and SpaceXAI: Grok 4.3 (batch)?
Anthropic: Claude Opus 5.5 can write up to 128K tokens (about 96,000 words) per response; SpaceXAI: Grok 4.3 (batch) up to 900K (about 675,000 words).
When were Anthropic: Claude Opus 5.5 and SpaceXAI: Grok 4.3 (batch) released?
Anthropic: Claude Opus 5.5 was listed on 2026-09-22; SpaceXAI: Grok 4.3 (batch) on 2026-04-30.
About the two models
Anthropic: Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...
Full Anthropic: Claude Opus 5.5 specs →SpaceXAI: Grok 4.3 (batch)
Grok 4.3 is a reasoning model from SpaceXAI. It accepts text and image inputs with text output, and is suited for agentic workflows, instruction-following tasks, and applications requiring high factual...
Full SpaceXAI: Grok 4.3 (batch) specs →