agentFast vs LangChain: What's the Difference?
LangChain is a toolkit of LLM building blocks — model wrappers, prompt templates, retrievers, chains, and integrations you assemble yourself. agentFast is an opinionated production layer with working agents on top of whichever orchestration SDK you choose. LangChain hands you parts; agentFast hands you an assembled, production-grade agent you can point at your data today.
Side by side
| LangChain | agentFast | |
|---|---|---|
| What it is | Composable LLM building blocks (OSS) | Production layer + working agents (source-available) |
| Level of assembly | You wire the pieces together | Assembled agents, wired end to end |
| Durable human-in-the-loop | Bring your own | ✓ Survives a crash, exactly-once |
| Observability + cost tracing | Via LangSmith (separate) | ✓ Built in, plus LangSmith export |
| Guardrails (PII, safety, rate limits) | Bring your own | ✓ Included |
| Evals in CI | Via LangSmith (separate) | ✓ Included, non-zero exit on breach |
| Working reference agents | Templates and examples | ✓ Support, Research, Code — on 5 SDKs |
They can coexist
agentFast is SDK-agnostic and often runs on LangChain's own orchestration (LangGraph). If you already use LangChain components, you keep them — agentFast adds the production plumbing around the agent, and even exports traces to LangSmith. The real question is whether you want to keep assembling infrastructure or start from an assembled one — the honest cost of rolling your own makes that trade-off concrete.
agentFast is the production layer — memory, 50 tools, observability, evals, guardrails, human-in-the-loop — for LangGraph, CrewAI, the Claude & OpenAI Agent SDKs & Vanilla. Own it for life.
Get agentFast — from $89