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Prompt optimization, finetuning, and reinforcement learning built by developers, for developers. Synth’s platform is designed to be serverless, composable, and human-usable by default.
  • Serverless: All of Synth’s algorithms are designed to work with your code with minimal affordances. If you can wrap your code in 3 simple HTTP routes, swap out your chat completions / responses url, and spin up a free Cloudflare tunnel, you can do GEPA, RL, and SFT.
  • Composable: Models trained and prompts calibrated in one session can be used in any other. Programmatically pipelining multiple training methods requires only a few SDK calls.
  • Human-usable: All methods provide the user with rich observability, cancellability, and where appropriate, interventions.

Highlights

  • 🚀 Serverless Training: Train across SFT, RL, and prompt optimization by standing up a single Cloudflare FastAPI wrapper around your code. No production code churn.
  • ⚡️ High Performance: Parallelize training and achieve 80% GPU utilization via PipelineRL
  • 🗂️ Multi-Experiment Management: Train prompts and models across multiple experiments with unified tracking
  • 🛠️ Local Development: Spin up experiment queues and datastores locally for dev work
  • 🔩 Serverless Training: Run training via CLI or programmatically without infrastructure management
  • 🏢 Enterprise Scale: Scales GPU-based model training to 64 H100s seamlessly
  • 💾 GEPA-Calibrated Judges: Use fast, accurate rubric scoring with GEPA-calibrated judges
  • 🖥️ Language Agnostic: Supports HTTP-based training across all programming languages
  • 🤖 CLI Integration: CLI utilities tuned for use with Claude Code, Codex, and Opencode
  • 📊 Comprehensive Tracking: Full observability with traces, metrics, and event logs

Quick Start

Get started with Synth AI in minutes:

Installation

Install Synth AI with uv:
uv add synth-ai
Or use via the CLI directly:
uvx synth-ai codex

What’s Next?