As of August 20, 2026, Laguna XS 2.1 is 57% cheaper per million tokens than Grok 4 Fast. Grok 4 Fast is $0.20 / $0.50 per million input/output tokens versus Laguna XS 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
xAI
Input
$0.20
Output
$0.50
Laguna XS 2.1
Poolside
Input
$0.10
Output
$0.20
Token pricing, specs, and benchmarks side by side
Grok 4 FastLaguna XS 2.1Verdict
Both models are closely matched on benchmarks. Laguna XS 2.1 has the pricing advantage, making it the better value unless Grok 4 Fast's specific capabilities are critical to your workflow.
As of August 20, 2026, Laguna XS 2.1 is 57% cheaper on blended LLM API pricing. Laguna XS 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 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 xAI API pricing is $0.20 input and $0.50 output per million tokens via xAI. Laguna XS 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.
Laguna XS 2.1 has a published SWE-bench Verified score of 70.9%. Grok 4 Fast does not have that eval on this page yet.
Grok 4 Fast supports a 2M token context window, while Laguna XS 2.1 supports 262K tokens. Grok 4 Fast 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 and Laguna XS 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 and Laguna XS 2.1 are production API models. For cost-sensitive production traffic, Laguna XS 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 through xAI and Laguna XS 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 supports up to 30K output tokens per request, while Laguna XS 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 has a measured throughput of approximately 90 tokens/second. Throughput data for Laguna XS 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 or Laguna XS 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 costs $0.20/M input and $0.50/M output. Laguna XS 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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