Grok 4.3 sits below the 4.5 and 4.6 flagships in xAI's line-up but beats both on one number that matters: it takes a million tokens of context, twice what they do, and costs less per token. xAI never gave it a launch post of its own — it simply appeared in the API catalogue, where it is still offered — so the only reliable description of it is the one in xAI's own documentation. Like the rest of the line it is billed on a two-tier scale: requests under 200,000 tokens are charged at the lower rate, and crossing that threshold reprices the entire request.