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L5 · Orchestration & Frameworks

HumanLayer

Human-in-the-loop API/SDK for AI agents to request human approvals and feedback.

Updated April 2026

Overview

Founded
2023
Headquarters
San Francisco, California
Segment
Tool Integration & Execution

Product overview

HumanLayer builds an open-source SDK (Python/TypeScript) and API enabling AI agents to integrate human oversight via decorators like @require_approval and human_as_tool, supporting channels like Slack, email, Discord.. It works with any LLM/framework for safe high-stakes actions in automations, agent oversight, and transitions to autonomy; used by teams for production-grade reliability. Distinct for tool-level human integration ensuring deterministic oversight without perfect LLM reliability, plus CodeLayer OSS IDE for coding agents in complex codebases. YC S24 backed, focuses on context engineering and 12-factor agents principles.

Revenue model

Freemium: Free Starter (100 ops/month, $20/200 extra), Premium $500/month; OSS core with enterprise custom integrations/support; credits-based pay-as-you-go..

Moat

  • Proprietary Technology
  • Switching Costs
  • Ecosystem Lock-in

HumanLayer's key competitive moat is its developer-first API and SDK that elegantly integrates human-in-the-loop workflows for reliable oversight in production AI agents, handling long-running asynchronous human approvals without locking users into a rigid ecosystem.

Headwinds

The company may struggle to achieve product-market fit as human-in-the-loop workflows could be seen as slowing down AI automation rather than enhancing it.