Extend alternatives
TL;DR: 12 companies doing similar work to Extend in B2B, ranked by how closely they match what Extend 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 Extend. They are scored on how closely their own description overlaps with Extend's, and all facts shown come from the YC company records — nothing is estimated.
What are the best alternatives to Extend?
| Alternative | What it does | Batch | Team | Status |
|---|---|---|---|---|
| Fithub | — | Winter 2010 | — | Inactive |
| Insoshi | — | Winter 2008 | — | Inactive |
| Optilly/Installmonetizer | Fb ad optimization platform | Winter 2012 | 11 | Inactive |
| Brushes | iPad drawing software. | Summer 2010 | — | Inactive |
| Reflex | The operating system for building mission-critical enterprise apps. | Winter 2023 | 10 | Active |
| Crocodoc | Embed PDFs, PowerPoints, and other documents into web and mobile apps | Winter 2010 | — | Acquired |
| GiveSpark | Givespark was a celebrity charity fundraising platform | Winter 2012 | 1 | Inactive |
| Envariant | Interpretability and reasoning infra for foundation models. | Winter 2026 | 1 | Active |
| Haystack | Replay real customer journeys against every change before you ship | Summer 2024 | 2 | Active |
| Lamb Labs | Lightning fast chips with hardcoded AI models | Summer 2026 | — | Active |
| OpenSpec | Plan mode for complex features | Winter 2026 | — | Active |
| Chartio | Chartio is changing how companies work by building the best… | Summer 2010 | 40 | Acquired |
Is Extend still active?
Extend 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 Extend. They are then ranked on how closely their own description overlaps with Extend's, so the closest matches come first rather than whoever happens to share a tag.