Which is cheaper, Claude Mythos 5 or GPT-5.3 Codex?
As of August 20, 2026, GPT-5.3 Codex is 74% cheaper on blended LLM API pricing. GPT-5.3 Codex costs $1.75 per million input tokens and $14.00 per million output tokens ($15.75 blended 1M-in + 1M-out). Claude Mythos 5 costs $10.00 / $50.00 per million tokens ($60.00 blended). Sources: https://platform.claude.com/docs/en/about-claude/pricing and https://developers.openai.com/api/docs/pricing. The cheapest LLM for your app still depends on how many output tokens you generate.
How much does Claude Mythos 5 vs GPT-5.3 Codex cost per million tokens?
Claude Mythos 5 Claude API pricing from Anthropic is $10.00 input and $50.00 output per million tokens via Anthropic. GPT-5.3 Codex OpenAI API pricing is $1.75 input and $14.00 output per million tokens via OpenAI. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Which is better for coding, Claude Mythos 5 or GPT-5.3 Codex?
Claude Mythos 5 leads on SWE-bench Verified: Claude Mythos 5 at 95.5% vs GPT-5.3 Codex at 74.8%. SWE-bench measures real GitHub fixes; LiveCodeBench measures contest programming.
What is the context window for Claude Mythos 5 vs GPT-5.3 Codex?
Claude Mythos 5 supports a 1M token context window, while GPT-5.3 Codex supports 400K tokens. Claude Mythos 5 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.
Which model performs better on benchmarks, Claude Mythos 5 or GPT-5.3 Codex?
Claude Mythos 5 leads on 10 of 11 shared benchmarks versus GPT-5.3 Codex's 1 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.
Is Claude Mythos 5 or GPT-5.3 Codex better for production use?
Both Claude Mythos 5 and GPT-5.3 Codex are production API models. For cost-sensitive production traffic, GPT-5.3 Codex 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.
Can I switch between Claude Mythos 5 and GPT-5.3 Codex in my app?
Yes. Call Claude Mythos 5 through Anthropic and GPT-5.3 Codex through OpenAI 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.
How accurate is this Claude Mythos 5 vs GPT-5.3 Codex pricing data?
List rates are the latest published Claude API pricing from Anthropic and OpenAI API pricing, quoted per million tokens. Official rate sheets: https://platform.claude.com/docs/en/about-claude/pricing and https://developers.openai.com/api/docs/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.
What is the output token limit for Claude Mythos 5 and GPT-5.3 Codex?
Claude Mythos 5 supports up to 128K output tokens per request, while GPT-5.3 Codex supports up to 128K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
Which model has better throughput, Claude Mythos 5 or GPT-5.3 Codex?
GPT-5.3 Codex has a measured throughput of approximately 50 tokens/second. Throughput data for Claude Mythos 5 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.
How do I switch the models in this Claude Mythos 5 vs GPT-5.3 Codex comparison?
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open Claude Mythos 5 or GPT-5.3 Codex from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
