Explore · The library

Every resource founders actually use, in one library.

The essays, videos, podcasts, books and tools behind every answer across eChai's hubs, from starting up to go-to-market, D2C, founder money and AI, each with a note on why it is here.

What founders use most, ranked by how many answers lean on it.

  1. The margin argument for charging on results instead of marking up tokens. hirefraction.com Article · How Founders Use AI AI Is Killing SaaS Margins. Outcome-Based Pricing Is How You Get Them Back. Fraction
  2. The founder behind the famous $0.99-per-resolution model on how it actually scaled. open.spotify.com Podcast · How Founders Use AI AI agent Fin nearing $100m revenue: Des Traynor Scaling Europe
  3. A reframe that changes pricing decisions: treat compute as growth investment, not just COGS. saastr.com Article · How Founders Use AI Inference is the New Sales and Marketing Spend SaaStr
  4. What happens to margins if you keep SaaS pricing on AI costs, with the numbers. saasmag.com Article · How Founders Use AI The AI COGS Problem: SaaS Gross Margin Compression SaaS Mag
  5. The single best ongoing feed to follow as AI pricing norms keep shifting. growthunhinged.com Guide · How Founders Use AI Growth Unhinged: pricing archive Kyle Poyar
  6. The leading open-source LLM observability platform: traces, costs, evals, and prompt management. langfuse.com Tool · How Founders Use AI Langfuse Langfuse
  7. A jargon-free primer on what you should be recording and why. langfuse.com Article · How Founders Use AI What is LLM Observability and Monitoring? Langfuse
  8. The managed alternative, strongest if you already build on LangChain. langchain.com Tool · How Founders Use AI LangSmith Observability LangChain
  9. A follow-along tutorial that gets tracing live in your app quickly. towardsdatascience.com Guide · How Founders Use AI LLM Monitoring and Observability: Hands-on with Langfuse Towards Data Science
  10. A current comparison so you choose once instead of migrating later. confident-ai.com Article · How Founders Use AI Top 7 LLM Observability Tools Confident AI
  11. Explains traces, spans, and generations with the main tools side by side. langflow.org Article · How Founders Use AI LLM Observability Explained (Langfuse, LangSmith, LangWatch) Langflow
  12. The operations chapter: daily habits of teams that keep LLM features healthy in production. oreilly.com Article · How Founders Use AI What We Learned from a Year of Building with LLMs (Part II): Operations Eugene Yan, Hamel Husain, et al.
  13. A menu of AI-specific metrics beyond DAUs, from acceptance rate to cost per active user. mixpanel.com Article · How Founders Use AI 30+ AI product metrics to track today Mixpanel
  14. Includes the killer diagnostic: compare AI-user retention curves against your product baseline. institutepm.com Guide · How Founders Use AI AI Product Metrics That Actually Matter Institute of Product Management
  15. Connects AI feature metrics to the board-level numbers investors ask about. thesaasbarometer.substack.com Article · How Founders Use AI AI Metrics that Matter in 2025 SaaS Barometer
  16. Last's first outside interview on the practical engineering of a reliable AI product at scale. open.spotify.com Podcast · How Founders Use AI How Notion Cofounder Simon Last Builds AI for Millions of Users AI and I (Dan Shipper, Every)
  17. A setup-to-dashboards walkthrough for self-hosting the free stack. prismix.dev Guide · How Founders Use AI Langfuse Guide: Open-Source LLM Observability and Tracing Prismix
  18. An India-based engineering firm's field guide to the metrics and tooling that matter. cloudraft.io Article · How Founders Use AI LLM Observability: Monitoring Large Language Models CloudRaft (India)
  19. Monitoring and optimization together, from an India-founded AI quality platform. getmaxim.ai Article · How Founders Use AI How to Reduce LLM Cost and Latency: A Practical Guide for Production AI Maxim AI (India)
  20. Updated adoption frameworks that treat AI feature usage as its own funnel. userpilot.com Article · How Founders Use AI How to Measure Product Adoption: Metrics for Human Users and AI Agents Userpilot
  21. Useful for B2B founders whose buyers now ask for AI usage reporting. capably.ai Article · How Founders Use AI Measuring AI Adoption Metrics Capably
  22. Why accuracy alone is a vanity metric and what to track instead. stackai.com Article · How Founders Use AI Measuring Enterprise AI Success: Essential KPIs Beyond Accuracy StackAI
  23. Video · How Founders Use AI How Perplexity works | Aravind Srinivas and Lex Fridman Lex Fridman
  24. Video · How Founders Use AI Can Perplexity beat Google? | Aravind Srinivas and Lex Fridman Lex Fridman

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The hubs

Starting Up Find an idea, validate it, build, and land your first customers. 1327 questions GTM Go-to-market, from breaking in to how the best teams do it. 379 questions D2C Building a direct-to-consumer brand, India-first. 512 questions Wealth Paying yourself, ESOPs, secondaries, and de-risking founder wealth. 165 questions How Founders Use AI How founders actually put AI to work, mapped topic by topic. 360 questions Glossary Plain-language definitions of the startup and VC terms you'll hit. 425 terms