As of August 25, 2026, Step-3.5-Flash is 97% cheaper per million tokens than Grok-3. Grok-3 is $3.00 / $15.00 per million input/output tokens versus Step-3.5-Flash at $0.10 / $0.40. Sources: https://docs.x.ai/docs/models and https://anotherwrapper.com/tools/llm-pricing
Sources: xAI API pricing (https://docs.x.ai/docs/models); AnotherWrapper LLM pricing (https://anotherwrapper.com/tools/llm-pricing)
Grok-3
xAI
Input
$3.00
Output
$15.00
Step-3.5-Flash
StepFun
Input
$0.10
Output
$0.40
Token pricing, specs, and benchmarks side by side
Each bar is share of the current leader on that eval. Click a row to open the board.
AIME 2025. Left is cheaper. Up is a higher score. The line is the best score you can buy at each price.
Grok-3Step-3.5-FlashVerdict
Step-3.5-Flash offers both lower pricing and stronger benchmark performance across the board, making it the clear value leader in this comparison.
As of August 25, 2026, Step-3.5-Flash is 97% cheaper on blended LLM API pricing. Step-3.5-Flash costs $0.10 per million input tokens and $0.40 per million output tokens ($0.50 blended 1M-in + 1M-out). Grok-3 costs $3.00 / $15.00 per million tokens ($18.00 blended). Sources: https://docs.x.ai/docs/models and https://anotherwrapper.com/tools/llm-pricing. The cheapest LLM for your app still depends on how many output tokens you generate.
Grok-3 xAI API pricing is $3.00 input and $15.00 output per million tokens via xAI. Step-3.5-Flash StepFun API pricing is $0.10 input and $0.40 output per million tokens via StepFun. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Step-3.5-Flash has a published SWE-bench Verified score of 74.4%. Grok-3 does not have that eval on this page yet.
Grok-3 supports a 128K token context window, while Step-3.5-Flash supports 66K tokens. Grok-3 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.
Step-3.5-Flash leads on 1 of 1 shared benchmarks versus Grok-3's 0 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-3 and Step-3.5-Flash are production API models. For cost-sensitive production traffic, Step-3.5-Flash 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-3 through xAI and Step-3.5-Flash through StepFun 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 StepFun API pricing, quoted per million tokens. Official rate sheets: https://docs.x.ai/docs/models and https://anotherwrapper.com/tools/llm-pricing. 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-3 supports up to 8K output tokens per request, while Step-3.5-Flash supports up to 8K 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-3 runs at approximately 100 tokens/second while Step-3.5-Flash runs at 150 tokens/second. Step-3.5-Flash is faster in raw throughput. 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-3 or Step-3.5-Flash 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-3 costs $3.00/M input and $15.00/M output. Step-3.5-Flash costs $0.10/M input and $0.40/M output.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
The index
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