AI-native research platform for arXiv and the wider literature
Search, summarise, and cross-link papers with an AI co-reader that surfaces related work, methods, and citations — built on top of arXiv and broader open repositories. PH launch 16 May 2026 with 29 votes.
| Directr tier | C | S | S | S |
| Price | Free / From $15/mo | Free (audit) / From $49/mo | Free / From $7/mo | Free / $44/yr |
| Free tier | Limited queries/mo | Audit most courses | Free | Limited credits |
| API access | ✗ | ✗ | ✗ | ✗ |
Access courses from Stanford, Google, and 300+ institutions — most auditable for free. Coursera Coach uses AI to answer questions mid-lesson, suggest what to study next, and summarise course material so you can move faster without missing the important parts. The standard route for self-directed professional development.
The world's most-used language learning app — now with AI conversation practice, personalised lesson paths, and an AI tutor for immersive speaking drills across 40+ languages. The gamification works better than most people expect, and the free tier is genuinely useful rather than a perpetual paywall tease.
Socratic AI tutor that asks guiding questions rather than handing over answers — because the research on learning strongly suggests that's how retention actually works. Covers maths, science, humanities, and coding with guardrails designed for learners of all ages. Backed by Khan Academy's deep expertise in what makes learning stick.