Cranston

Cranston is a Y Combinator (Fall 2025) startup building an AI back office for CPA firms. Rather than one tool, it aims to be a single operating layer across tax prep, tax review, bookkeeping, client requests and practice management, running on top of QuickBooks and the tax software firms already use.

What it does well, on the evidence so far: it targets the whole firm back office, the expensive, manual middle of a practice, and offers a flexible model, use it with your own team or hire Cranston's accountants as a white-label back office. It works alongside existing systems rather than replacing them, which lowers the barrier to trying it.

Where to be cautious: it is very early-stage, with only a handful of customers and modest early revenue, so independent reviews are essentially not yet available and the product is still maturing. Firm back-office work is high-stakes, so accuracy and review need close attention.

Best for: small and growing CPA and accounting firms open to being early adopters of an AI-run back office.

Verdict: an ambitious, promising bet on automating the CPA firm back office, but a young one. Pilot it on a slice of work you can check, and judge it on real accuracy and time saved as it grows.