ds2api vs Libretto

ds2api is a lightweight Go middleware server that acts as a protocol translation layer between AI clients and multiple provider APIs. It accepts requests in any major client format and converts them to the target provider format — covering OpenAI, Anthropic Claude, Google Gemini, and others. Multi-account rotation is built in: you can pool API keys across accounts to spread load and reduce rate-limit exposure. The project is minimal by design — a single Go binary that runs locally or in a container. It's aimed at developers and teams who work with multiple AI providers and want a single endpoint that handles format conversion and key rotation transparently. No vendor lock-in, no cloud dependency. ds2api is gaining traction in the local LLM and API arbitrage communities who run self-hosted models alongside commercial APIs and need a clean routing layer. The multi-account rotation feature is particularly relevant for power users who maintain multiple accounts across providers to work around per-account rate limits — a controversial-but-common practice.

Libretto is an open-source browser automation toolkit built by Saffron Health to solve a critical problem with AI-driven web agents: non-determinism. Standard agent-controlled browsers using Playwright or Puppeteer routinely fail 20-30% of the time on production workflows because they rely on LLM judgment for timing and element selection. Libretto replaces that with a record-replay system that captures precise interaction timing and DOM fingerprints, achieving a reported 95% success rate on identical workflows. The library works by recording a "golden path" of a browser session — capturing not just actions but the exact CSS selectors, visual context, and timing windows during which those actions are valid. On replay, it verifies each step against expected page state before proceeding, and falls back to an LLM-assisted recovery mode when pages drift (e.g., after a UI update). Saffron Health built it to maintain integrations with EHR portals that change frequently and where failure has compliance consequences. Saffron open-sourced Libretto after using it internally for 18 months across 40+ healthcare software integrations. The HN thread highlighted the appeal for fintech, legal, and healthcare automation where reliability, not just capability, is the product. The toolkit targets TypeScript/Node.js environments and integrates cleanly with existing Playwright infrastructure.