As of August 20, 2026, Laguna S 2.1 is 57% cheaper per million tokens than Grok-4 Fast Reasoning. Grok-4 Fast Reasoning is $0.20 / $0.50 per million input/output tokens versus Laguna S 2.1 at $0.10 / $0.20. Sources: https://docs.x.ai/docs/models and https://poolside.ai
Sources: xAI API pricing (https://docs.x.ai/docs/models); Poolside pricing (https://poolside.ai)
Grok-4 Fast Reasoning
xAI
Input
$0.20
Output
$0.50
Laguna S 2.1
Poolside
Input
$0.10
Output
$0.20
Token pricing, specs, and benchmarks side by side
Grok-4 Fast ReasoningLaguna S 2.1Verdict
Both models are closely matched on benchmarks. Laguna S 2.1 has the pricing advantage, making it the better value unless Grok-4 Fast Reasoning's specific capabilities are critical to your workflow.
As of August 20, 2026, Laguna S 2.1 is 57% cheaper on blended LLM API pricing. Laguna S 2.1 costs $0.10 per million input tokens and $0.20 per million output tokens ($0.30 blended 1M-in + 1M-out). Grok-4 Fast Reasoning costs $0.20 / $0.50 per million tokens ($0.70 blended). Sources: https://docs.x.ai/docs/models and https://poolside.ai. The cheapest LLM for your app still depends on how many output tokens you generate.
Grok-4 Fast Reasoning xAI API pricing is $0.20 input and $0.50 output per million tokens via xAI. Laguna S 2.1 Poolside API pricing is $0.10 input and $0.20 output per million tokens via Poolside. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Grok-4 Fast Reasoning has a published SWE-bench Verified score of 45.4%. Laguna S 2.1 does not have that eval on this page yet.
Grok-4 Fast Reasoning supports a 2M token context window, while Laguna S 2.1 supports 1M tokens. Grok-4 Fast Reasoning offers a larger context window. Filling a larger window bills more input tokens, so the cheaper-per-million model can still cost more on long documents.
Shared benchmark scores for Grok-4 Fast Reasoning and Laguna S 2.1 are still limited. Check the comparison table for the evals each model has published. Check the comparison table for GPQA Diamond, SWE-bench, MMLU, HLE, and the other evals we track. Token price and benchmark score together are the usual LLM comparison, not either number alone.
Both Grok-4 Fast Reasoning and Laguna S 2.1 are production API models. For cost-sensitive production traffic, Laguna S 2.1 has better economics on the blended 1M-in + 1M-out scale. For maximum capability, weight the benchmark table for your domain. Many production stacks route cheap models for drafts and a frontier model for the hard turn, which is usually cheaper than sending everything to the expensive API.
Yes. Call Grok-4 Fast Reasoning through xAI and Laguna S 2.1 through Poolside with separate API keys, or through a gateway that already wraps both. Keep prompts in tokens, not characters, when you estimate the invoice. AnotherWrapper templates can swap providers without rewriting auth and billing.
List rates are the latest published xAI API pricing and Poolside API pricing, quoted per million tokens. Official rate sheets: https://docs.x.ai/docs/models and https://poolside.ai. Prompt caching, batch APIs, and committed-use discounts can change the invoice. Benchmark scores are from official publications and independent evals, updated as new numbers land.
Grok-4 Fast Reasoning supports up to 30K output tokens per request, while Laguna S 2.1 supports up to an unspecified number of output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
Grok-4 Fast Reasoning has a measured throughput of approximately 90 tokens/second. Throughput data for Laguna S 2.1 is not yet available. Throughput (tokens per second) and time-to-first-token are why two models with the same per-million-token price can still feel different in chat and agents.
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open Grok-4 Fast Reasoning or Laguna S 2.1 from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
This comparison covers API pricing, context window, throughput, and benchmark scores. Grok-4 Fast Reasoning costs $0.20/M input and $0.50/M output. Laguna S 2.1 costs $0.10/M input and $0.20/M output.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
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