LangChain vs Fly.io

LangChain

Fly.io

LangChain · 18 features

• Agents — Tool-using agents with reasoning loops.
• Chains (LCEL) — LangChain Expression Language — pipe primitives into chains.
• Checkpointers (LangGraph) — Persist agent state to SQL, Mongo, Redis, Postgres.
• Document Loaders — 150+ loaders for PDF, HTML, Notion, Google Drive, S3, GitHub, etc.
• Human-in-the-loop — Pause agent for approval, then resume.
• LangGraph — Stateful graph-based agent runtime. Durable, replayable, human-in-the-loop.
• LangGraph Platform — Managed hosting for LangGraph agents with state persistence.
• LangGraph Studio — Desktop IDE for debugging agent graphs.
• LangServe — Deploy chains as FastAPI endpoints.
• Memory — Buffer, summary, entity, vector memory stores.
• Output Parsers — Structured JSON, Pydantic schemas, function calling.
• Prompt Templates — Templating + partial filling + output parsers.
• RAG (Retrieval-Augmented Generation) — Standard patterns + 50+ retrievers.
• Streaming — First-class streaming at every layer.
• Subgraphs — Compose agent graphs hierarchically.
• Text Splitters — Recursive, token, semantic splitters for chunking.
• Tools — 400+ pre-built tools (web search, code, databases, APIs).
• Vector Store Integrations — 60+ vector DBs (Pinecone, Chroma, Weaviate, PGVector, Qdrant, Milvus).

Fly.io · 14 features

• Auto Stop/Start — Machines auto-stop when idle, start on request (like scale-to-zero).
• Certs — Let's Encrypt + wildcard certs managed.
• Fly GPU — A100/L40S/A10 on-demand GPU machines.
• Fly Kubernetes (FKS) — Managed Kubernetes on Fly machines.
• Fly Machines — Firecracker microVMs. Start in <1s. Run any Docker image.
• Fly Postgres — Managed Postgres via Supabase partnership (2024). Also legacy self-run Postgres …
• fly-replay headers — Route request to another region at app level.
• Fly Volumes — Persistent SSD attached to a Machine. Encrypted at rest.
• Global Anycast — Single IP routes to the closest region automatically.
• LiteFS — Distributed SQLite with primary/replica across regions.
• Private Networks — 6PN WireGuard mesh. Connect machines across regions privately.
• Secrets — Encrypted env vars propagated to all regions.
• Tigris (partner) — S3-compatible storage for Fly apps. By partner.
• Upstash Redis (partner) — Managed Redis via Upstash.