Codex vs Claude Code: 54 vs 9 Real Businesses, and Why Most Codex Users Run Both
Claude Code appears in 54 revenue-backed businesses and Codex in 9, and most Codex users run Claude Code too. Why founders add Codex, and what each costs.
Among founders with real revenue, Claude Code is the primary tool and Codex is usually the second one. The ProvenStartups index holds 54 revenue-backed businesses built or run with Claude Code and 9 with OpenAI's Codex, and 4 of those Codex businesses also use Claude Code. Nobody in our data chose Codex *instead of* Claude Code on principle. They added it to get past usage limits, to save money, or after switching tools.
How we count: a business is listed only if its own interview says the tool built or runs the product. On October 17, 2026 we removed half of the Codex mentions: sales pitches that "you can build this with ChatGPT Codex," either/or mentions, a product that merely launches Codex agents, and a writing app that happens to be called Codex Heim.
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Which do profitable founders use: Codex or Claude Code?
Claude Code, by volume and by evidence. The table below puts both cohorts on the same yardstick and updates as businesses are added; the Codex side is too small for a median.
Here is every Codex business in the index, with what Codex actually does in each:
