Compare AI tools

	Perplexity S	Stripe Link A	Lex A	NotebookLM S
Tagline	AI search done right. Cited answers, not chat theater.	A digital wallet that lets AI agents spend on your behalf — without ever seeing your actual card number.	Google Docs with an AI collaborator baked in.	Google's research notebook. Turns your docs into a podcast.
Category	Research	Agents	Writing	Research
Pricing	Free + $20/mo Pro	Free for consumers; standard Stripe per-transaction fees for merchants	Free + $12/mo	Free
Best for	Replacing Google for any question where you want a cited answer in seconds.	Anyone running autonomous AI agents (shopping bots, booking assistants, personal AI) who wants delegated payment capability without handing over raw card data.	Essays, long-form drafts, thinking on the page.	Students, researchers, anyone with a stack of PDFs or a topic to learn.
Strengths	Sources every claim Fast, current answers Pro Search runs multi-step research Spaces for persistent context	First mainstream wallet with a built-in agent authorization layer — AI agents get one-time-use cards, not your real credentials OAuth-based approval flow means you review every agent spend request before payment credentials are shared 250M+ existing Link users means instant network coverage at hundreds of thousands of Stripe-powered merchants Developer-friendly: agent builders can use Link's wallet infra instead of rolling their own payment rails Subscription tracking, auto payment-method updates, and 90-day purchase protection bundled in	Clean writing UX — distraction-free +++ prompt triggers AI help Collaboration + AI feedback together	Upload anything, ask questions, get cited answers Audio Overview turns docs into a 10-min podcast Great for studying
Weaknesses	Not a general chatbot Answers can be shallow on complex topics	Stablecoin, agentic token, and BNPL agent-payment support is still 'coming soon' — traditional cards only at launch Per-transaction approval flow can be tedious for high-frequency agent tasks until spending-limit presets ship Merchant adoption for agent checkout paths is still early; real-world agentic commerce coverage is thin	Less feature-rich than Google Docs AI ceiling below dedicated tools	Google-only Can be slow on large corpora
Kai's verdict	S-tier for search. I use it before Google now. If you're still Googling everything, try this for a week.	Stripe Link is the most credible first move toward a real agentic payment layer — the one-time-use card model is genuinely clever, and the existing merchant network gives it a head start no startup wallet can match. But the 'approve every transaction' UX will get old fast, and the hard part (autonomous spending with guardrails) is still on the roadmap. (Verdict pending Phi's full review.)	A-tier. Beautiful UX. The writing app I'd pick if I only wrote long-form.	S-tier for study. The Audio Overview is a killer feature. Try it with three of your favorite PDFs.
Link	Open →	Open →	Open →	Open →