As of August 20, 2026, Grok 4 Fast is 53% cheaper per million tokens than Inkling-Small. Grok 4 Fast is $0.20 / $0.50 per million input/output tokens versus Inkling-Small at $0.30 / $1.20. Sources: https://docs.x.ai/docs/models and https://thinkingmachines.ai
Sources: xAI API pricing (https://docs.x.ai/docs/models); Thinking Machines Lab pricing (https://thinkingmachines.ai)
Grok 4 Fast
xAI
Input
$0.20
Output
$0.50
Inkling-Small
Thinking Machines
Input
$0.30
Output
$1.20
Token pricing, specs, and benchmarks side by side
Grok 4 FastInkling-SmallVerdict
Grok 4 Fast offers significantly lower pricing, while Inkling-Small leads on benchmark performance. Your choice depends on whether cost efficiency or raw capability matters more for your use case.
As of August 20, 2026, Grok 4 Fast is 53% cheaper on blended LLM API pricing. Grok 4 Fast costs $0.20 per million input tokens and $0.50 per million output tokens ($0.70 blended 1M-in + 1M-out). Inkling-Small costs $0.30 / $1.20 per million tokens ($1.50 blended). Sources: https://docs.x.ai/docs/models and https://thinkingmachines.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. Inkling-Small Thinking Machines Lab API pricing is $0.30 input and $1.20 output per million tokens via Thinking Machines Lab. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Inkling-Small has a published SWE-bench Verified score of 80.2%. Grok 4 Fast does not have that eval on this page yet.
Grok 4 Fast supports a 2M token context window, while Inkling-Small supports 256K 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.
Inkling-Small leads on 7 of 9 shared benchmarks versus Grok 4 Fast's 2 wins. 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 Inkling-Small are production API models. For cost-sensitive production traffic, Grok 4 Fast 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 Inkling-Small through Thinking Machines Lab 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 Thinking Machines Lab API pricing, quoted per million tokens. Official rate sheets: https://docs.x.ai/docs/models and https://thinkingmachines.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 Inkling-Small supports up to 256K 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 Inkling-Small 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 Inkling-Small 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. Inkling-Small costs $0.30/M input and $1.20/M output via Thinking Machines Lab.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
The index
280 models across 33 providers. Search or jump to a lab — every model page stays linked here.
Next step
Auth, billing, and the API layer are already decided. Fork 8 finished AI apps, or have us build the first version with you.
