Rex alternatives
TL;DR: 12 companies doing similar work to Rex in B2B, ranked by how closely they match what Rex actually does — not just by category.
How this list was built: every company here is Y Combinator-backed and shares at least one category with Rex. They are scored on how closely their own description overlaps with Rex's, and all facts shown come from the YC company records — nothing is estimated.
What are the best alternatives to Rex?
| Alternative | What it does | Batch | Team | Status |
|---|---|---|---|---|
| Sigma | Lakehouse-as-a-Service (LaaS) for pre and post-acquisition | Fall 2026 | 2 | Active |
| Scanate/Fellow | API for Invoice Financing | Summer 2016 | 2 | Inactive |
| Fithub | — | Winter 2010 | — | Inactive |
| Insoshi | — | Winter 2008 | — | Inactive |
| Minerva | AI native financial institution | Spring 2025 | 5 | Active |
| Finmark | Financial planning software for startups | Summer 2020 | 14 | Acquired |
| BHRD | BHRD ("Be Heard") helps public companies communicate with investors. | Summer 2018 | 3 | Inactive |
| Maroo | CRM for creatives (acquired by Helium Ventures) | Summer 2021 | 5 | Acquired |
| Simetrik | No code enterprise SaaS for financial control automation. | Winter 2018 | 350 | Active |
| Cashboard | Inventing the solo CFO. | Summer 2022 | 6 | Active |
| FullSeam | AI agents for corporate accounting teams | Winter 2026 | 3 | Active |
| Sintropix | Autonomous accounting platform for global companies | Fall 2026 | 2 | Active |
Is Rex still active?
Rex is still operating, so switching is a choice rather than a forced migration. Compare on fit and price rather than urgency.
How was this list put together?
Every company here is Y Combinator-backed and shares at least one category with Rex. They are then ranked on how closely their own description overlaps with Rex's, so the closest matches come first rather than whoever happens to share a tag.