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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. Diagram-first explanations your whole team can absorb in ten minutes. pub.towardsai.net Article · How Founders Use AI 8 LLM Cost Optimization Techniques, Visually Explained Divy Yadav (Towards AI)
  2. A gateway gives you routing, fallbacks, and spend visibility in one move; this compares the options. helicone.ai Article · How Founders Use AI Top 5 LLM Gateways in 2025 Helicone
  3. A sober side-by-side of per-token prices across the big three, including budget tiers. intuitionlabs.ai Article · How Founders Use AI LLM API Pricing Comparison (2025): OpenAI, Gemini, Claude IntuitionLabs
  4. A builder's receipts: one technique, a 90% real bill reduction, with the code that did it. medium.com Article · How Founders Use AI Prompt Caching is a Must: From $720 to $72 Monthly Du'An Lightfoot
  5. Actual production numbers for agent workloads, the costliest and least predictable AI feature type. medium.com Article · How Founders Use AI The Unit Economics of AI Agents: Budgeting LLM Costs with Real Numbers Nikhil Sood
  6. Understand your supplier's economics to predict where API prices go next. exponentialview.co Article · How Founders Use AI X-raying OpenAI's unit economics Azeem Azhar (Exponential View)
  7. A structured comparison across reasoning, coding, context, and compliance rather than hype. intuitionlabs.ai Article · How Founders Use AI Claude vs ChatGPT vs Copilot vs Gemini: Enterprise Guide IntuitionLabs
  8. Side-by-side output quality on real writing tasks, the kind of eval founders should copy. blog.type.ai Article · How Founders Use AI Who Wrote it Better? Claude vs ChatGPT vs Gemini Type.ai
  9. Explains what each benchmark measures so you stop choosing models on a single headline number. futureagi.com Article · How Founders Use AI LLM Benchmarks: GPT-5, Claude, Gemini, Grok compared Future AGI
  10. A serving-infrastructure company's practical map of the open-weight landscape. bentoml.com Article · How Founders Use AI The Best Open-Source LLMs BentoML
  11. A decision framework for the open-vs-closed call, written for teams shipping to customers. techcommunity.microsoft.com Article · How Founders Use AI Comparing Open-Source vs Closed LLMs for Enterprise Apps Microsoft
  12. Covers the hybrid pattern most teams actually land on: closed for frontier tasks, open for private or high-volume ones. hakia.com Article · How Founders Use AI Open Source vs Closed LLMs: Technical Comparison Hakia
  13. From an India-founded ML platform: how gateways make model choice reversible. truefoundry.com Article · How Founders Use AI Helicone vs OpenRouter: Key Differences TrueFoundry
  14. The lock-in insurance layer compared hands-on, including India-built Portkey. klymentiev.com Guide · How Founders Use AI LLM Gateway guide: OpenRouter vs LiteLLM vs Portkey vs Helicone Dmytro Klymentiev
  15. A second, eval-minded view on routing layers so you can switch providers in an afternoon. braintrust.dev Article · How Founders Use AI 6 best LLM gateways for developers Braintrust
  16. A regularly refreshed plain-English rundown of the current frontier models and their sweet spots. codingscape.com Article · How Founders Use AI Most powerful LLMs (Large Language Models) Codingscape
  17. The essay that made evals a founder-level topic; failed LLM products almost always skipped this. hamel.dev Article · How Founders Use AI Your AI Product Needs Evals Hamel Husain
  18. A free written masterclass version if you want the method without the course fee. aakashg.com Guide · How Founders Use AI How to Master AI Evals: Step-by-Step with Hamel and Shreya Aakash Gupta (Product Growth)
  19. Gets your first automated eval running in under an hour. datacamp.com Guide · How Founders Use AI Promptfoo Tutorial: A Hands-On Guide to LLM Evaluation DataCamp
  20. A current map of the eval tooling landscape so you pick once, correctly. braintrust.dev Article · How Founders Use AI Best Prompt Evaluation Tools (Tested and Compared) Braintrust
  21. A conversational companion to Hamel's essay with concrete team workflows. humanloop.com Article · How Founders Use AI Why Your AI Product Needs Evals, with Hamel Husain Humanloop
  22. Distils the conference's eval takeaways, including hunting implicit user feedback signals. vellum.ai Article · How Founders Use AI Big Ideas from the AI Engineer World's Fair Vellum
  23. How to make your AI coding tools carry the eval workload for you. hamelhusain.substack.com Article · How Founders Use AI Evals Skills for Coding Agents Hamel Husain
  24. Turning evals into a deploy gate so a bad prompt change never reaches users. braintrust.dev Article · How Founders Use AI Best AI Eval Tools for CI/CD Pipelines Braintrust

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The hubs

Starting Up Find an idea, validate it, build, and land your first customers. 1046 questions GTM Go-to-market, from breaking in to how the best teams do it. 352 questions D2C Building a direct-to-consumer brand, India-first. 482 questions Wealth Paying yourself, ESOPs, secondaries, and de-risking founder wealth. 154 questions How Founders Use AI How founders actually put AI to work, mapped topic by topic. 278 questions Glossary Plain-language definitions of the startup and VC terms you'll hit. 390 terms
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