As of August 20, 2026, Grok Code Fast 1 is 90% cheaper per million tokens than GPT-5.4. GPT-5.4 is $2.50 / $15.00 per million input/output tokens versus Grok Code Fast 1 at $0.20 / $1.50. Sources: https://developers.openai.com/api/docs/pricing and https://docs.x.ai/docs/models
Sources: OpenAI API pricing (https://developers.openai.com/api/docs/pricing); xAI API pricing (https://docs.x.ai/docs/models)
GPT-5.4
OpenAI
Input
$2.50
Output
$15.00
Grok Code Fast 1
xAI
Input
$0.20
Output
$1.50
Token pricing, specs, and benchmarks side by side
GPT-5.4Grok Code Fast 1Verdict
Grok Code Fast 1 offers significantly lower pricing, while GPT-5.4 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 Code Fast 1 is 90% cheaper on blended LLM API pricing. Grok Code Fast 1 costs $0.20 per million input tokens and $1.50 per million output tokens ($1.70 blended 1M-in + 1M-out). GPT-5.4 costs $2.50 / $15.00 per million tokens ($17.50 blended). Sources: https://developers.openai.com/api/docs/pricing and https://docs.x.ai/docs/models. The cheapest LLM for your app still depends on how many output tokens you generate.
GPT-5.4 OpenAI API pricing is $2.50 input and $15.00 output per million tokens via OpenAI. Grok Code Fast 1 xAI API pricing is $0.20 input and $1.50 output per million tokens via xAI. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
GPT-5.4 leads on SWE-bench Verified: GPT-5.4 at 76.9% vs Grok Code Fast 1 at 70.8%. SWE-bench measures real GitHub fixes; LiveCodeBench measures contest programming.
GPT-5.4 supports a 1M token context window, while Grok Code Fast 1 supports 256K tokens. GPT-5.4 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.
GPT-5.4 leads on 5 of 5 shared benchmarks versus Grok Code Fast 1'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 GPT-5.4 and Grok Code Fast 1 are production API models. For cost-sensitive production traffic, Grok Code Fast 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 GPT-5.4 through OpenAI and Grok Code Fast 1 through xAI 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 OpenAI API pricing and xAI API pricing, quoted per million tokens. Official rate sheets: https://developers.openai.com/api/docs/pricing and https://docs.x.ai/docs/models. 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.
GPT-5.4 supports up to 128K output tokens per request, while Grok Code Fast 1 supports up to 10K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
GPT-5.4 runs at approximately 50 tokens/second while Grok Code Fast 1 runs at 76.41 tokens/second. Grok Code Fast 1 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 GPT-5.4 or Grok Code Fast 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. GPT-5.4 costs $2.50/M input and $15.00/M output. Grok Code Fast 1 costs $0.20/M input and $1.50/M output.
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.
