AtCoder vs Greenhouse vs HackerRank vs Obsidian
| Attribute | ||||
|---|---|---|---|---|
| Category | Education & Learning | HR & Recruiting | HR & Recruiting | Note-taking & Knowledge |
| Pricing | Free tier | Paid | Paid | Free tier |
| Starting price | Free | — | — | $4/seat/month |
| Free tier | Yes | No | No | Yes |
| Free trial | No | Yes | No | No |
| Deployment | — | — | — | Cloud |
| API available | Unknown | Unknown | Unknown | Unknown |
| Platforms | — | — | — | ios, android, windows, macos, linux |
| Certifications | — | — | — | — |
| Integrations | — | 3 | — | 2 |
| Company | — | — | Founded 2012 | Founded 2020 |
| Feature attributes | ||||
Also consider
Unknown values show as “Unknown”/“—”. Nothing is inferred — see each tool page for sources.