GitHub – Merit-Systems/Echo: The User Pays AI SDK

User-pays AI infrastructure. Drop in Echo, users pay for their own usage—you never front costs. Skip the hard choice between fronting API costs, high-friction BYOK flows, or building billing from scratch. Read the docs | Live demo | Read our announcement Building AI apps forces you to pick your poison: | Approach | Developer Cost | User Experience | Revenue Model | |---|---|---|---| | BYOK | None (but no revenue) | Complex key management | None | | Dev API Key | Unpredictable burn rate | Simple | Need metering + billing | | Bill End Users | Weeks building infra | Simple | Auth + Stripe + metering | Echo eliminates all three problems. Replace your AI SDK imports with Echo. Users authenticate once, get a balance, and pay for their own usage. You set a markup and earn revenue automatically. Before: // Option 1: Front costs yourself import { openai } from '@ai-sdk/openai'; import { generateText } from 'ai'; const response = await generateText({ model: openai('gpt-5'), 'YOUR-API-KEY', prompt: '...' }); After: // Users pay, you earn markup, zero infrastructure import { useEchoModelProviders } from '@merit-systems/echo-react-sdk'; import { generateText } from 'ai'; const { openai } = useEchoModelProviders(); const response = await generateText({ model: openai('gpt-5'), prompt: '...', }); pnpx echo-start@latest Creates a new app with Echo pre-configured. Live in 2 minutes. No hosting costs - Users pay providers directly through Echo. You never proxy requests or front bills. Better UX - One OAuth login replaces complex BYOK flows. Users get a universal balance across all Echo apps. Instant revenue - Set a markup percentage. Every token generates profit automatically. Zero infrastructure - No payment processing, no usage tracking, no key validation. Echo handles it all. - Echo Control: Next.js app for echo.merit.systems. Hosted site and api routes. - Echo Server: Express server for router.echo.merit.systems. Proxy for routing and metering LLM requests from clients. - Echo TS SDK Typescript SDK that all the framework specific SDKs are built on top of. - Echo Next.js SDK SDK for simple Next.js 15+ App Router integration. - Echo React SDK SDK for simple React client side SPA integration. Get started quickly with echo-start : pnpx echo-start gen-ai-app Available templates: - next - Next.js application with Echo - react - Vite React application with Echo - next-chat - Next.js chatbot with Echo and Vercel AI SDK - assistant-ui - Next.js with Echo and Assistant UI - echo-cli - CLI tool for AI chat with Echo (API keys + crypto wallets) Or run npx echo-start my-app to choose interactively. Note: The CLI template (echo-cli ) requires manual installation from the repository as it's a command-line tool rather than a web application. See the templates README for details. Fill out packages/app/control/.env and packages/app/server/.env . Then... pnpm i pnpm dev