Choose Anthropic: Claude Sonnet 5.5 if…
- you want the newer model — released 2026-09-28, 5 months after the other
Anthropic: Claude Sonnet 5.5 vs SpaceXAI: Grok 4.3 (batch)
Neither wins outright: Anthropic: Claude Sonnet 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 Sonnet 5.5 | SpaceXAI: Grok 4.3 (batch) |
|---|---|---|
| Provider | Anthropic | X Ai |
| Input price (per 1M tokens) | $2.00 | $1.00 |
| Output price (per 1M tokens) | $10.00 | $2.00 |
| Blended price (3:1 input/output) | $4.00 | $1.25 |
| Cheaper than … of all models we track | 15% | 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 | 2026-09-28 | 2026-04-30 |
Advertisement
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 Sonnet 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) | $350 | $115 | SpaceXAI: Grok 4.3 (batch) saves $235 |
| RAG search over documents 20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens) | $340 | $140 | SpaceXAI: Grok 4.3 (batch) saves $200 |
| 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) | $360 | $144 | SpaceXAI: Grok 4.3 (batch) saves $216 |
| Batch summarisation 10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens) | $220 | $92.00 | SpaceXAI: Grok 4.3 (batch) saves $128 |
| Long-document analysis 500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens) | $110 | $52.00 | SpaceXAI: Grok 4.3 (batch) saves $58.00 |
Capabilities side by side
| Capability | Anthropic: Claude Sonnet 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 Sonnet 5.5: price unchanged since we started tracking it on 2026-09-29.
- 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 69% cheaper on a typical 3:1 input/output mix ($115 vs $350 a month for 50,000 support chats)
- you need seed (reproducible sampling) — to repeat a generation for tests and evals; Anthropic: Claude Sonnet 5.5 does not advertise it
- you need log-probabilities — to read token confidence for classification and scoring; Anthropic: Claude Sonnet 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 Sonnet 5.5 better than SpaceXAI: Grok 4.3 (batch)?
Neither wins outright: Anthropic: Claude Sonnet 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 Sonnet 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 Sonnet 5.5 or SpaceXAI: Grok 4.3 (batch)?
SpaceXAI: Grok 4.3 (batch) is cheaper: $1.25 vs $4.00 per 1M tokens at a typical 3:1 input/output mix, 69% less. For 50,000 support conversations a month that is $115 against $350.
How much do Anthropic: Claude Sonnet 5.5 and SpaceXAI: Grok 4.3 (batch) cost per million tokens?
Anthropic: Claude Sonnet 5.5 costs $2.00 per 1M input tokens and $10.00 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 Sonnet 5.5 or SpaceXAI: Grok 4.3 (batch)?
Both take 1M tokens per request — roughly 1,500 pages of text.
Do Anthropic: Claude Sonnet 5.5 and SpaceXAI: Grok 4.3 (batch) support function calling and JSON output?
Tool calling — Anthropic: Claude Sonnet 5.5: yes, SpaceXAI: Grok 4.3 (batch): yes. JSON-schema structured output — Anthropic: Claude Sonnet 5.5: yes, SpaceXAI: Grok 4.3 (batch): yes.
Can Anthropic: Claude Sonnet 5.5 or SpaceXAI: Grok 4.3 (batch) read images?
Yes, both accept image input.
Is Anthropic: Claude Sonnet 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 Sonnet 5.5 and SpaceXAI: Grok 4.3 (batch)?
Anthropic: Claude Sonnet 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 Sonnet 5.5 and SpaceXAI: Grok 4.3 (batch) released?
Anthropic: Claude Sonnet 5.5 was listed on 2026-09-28; SpaceXAI: Grok 4.3 (batch) on 2026-04-30.
About the two models
Anthropic: Claude Sonnet 5.5
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing...
Full Anthropic: Claude Sonnet 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 →