Heym

Build agentic systems. Run them with confidence.

Heym is a self-hosted runtime and platform for building, orchestrating, running, observing, evaluating, and controlling agentic systems on your infrastructure.

Visually compose agents and deterministic workflows, or generate them with AI. Connect models, tools, MCP, company knowledge, and internal systems, then operate them with approval checkpoints, retries, and visibility into execution and model costs.

heym.run

Try locally: git clone https://github.com/heymrun/heym.git && cd heym && ./run.sh Quick Start · Deploy & Call Workflows · Extending Heym · Security

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What Is Heym?

In Heym, a workflow defines how agents, deterministic steps, tools, and data work together. The runtime executes that graph, coordinates dependent and parallel work, records execution history, and supports human review checkpoints.

The canvas is one interface into Heym. It is not Heym itself. Use it to build, inspect, debug, and understand systems running on the runtime. Those same workflows also run through APIs, schedules, event triggers, MCP clients, and Portal conversations.

Explore the product site at heym.run.

One Runtime for the Agent Lifecycle

Build → Orchestrate → Run → Observe → Evaluate → Control → Expose

These are connected parts of operating an agentic system in Heym.

Stage	What you do in Heym
Build	Compose agents and deterministic workflows visually, generate them with AI, or start from reusable templates and skills.
Orchestrate	Coordinate agents, sub-agents, sub-workflows, and tools with explicit data flow, branching, and parallel execution where dependencies allow.
Run	Execute from APIs, schedules, event triggers, or interactive interfaces, with configurable retries, error paths, and browser automation.
Observe	Inspect execution history, live state, traces, tool calls, tokens, latency, errors, and model costs. Review analytics and alerts, and export OpenTelemetry traces.
Evaluate	Test prompts and model responses against expected outputs, compare results across models, and inspect saved evaluation runs.
Control	Pause Agent execution at review checkpoints and resume from saved state after a human decision. Configure guardrails, credentials, authentication, and team access.
Expose	Serve workflows through REST, SSE streaming, MCP tools, and Portal chat interfaces, or connect their results to in-app dashboard widgets.

Use observations and evaluation results to refine prompts, tools, and workflow logic, then run and inspect the next iteration.

🗺️ Platform Overview

The workflow definition connects the build experience to execution. The runtime uses that definition to coordinate nodes and tools, while execution state feeds the interfaces people use to inspect, review, and consume the results.

Part of the system	How it fits
Build and inspect	The canvas, AI Assistant, templates, and Expression DSL create and edit workflow definitions. The same canvas can attach to an active execution for inspection.
Orchestrate and execute	The executor coordinates agents, deterministic nodes, sub-workflows, parallel branches, retries, and review checkpoints.
Connect tools and data	Nodes and agent tools reach models, HTTP APIs, MCP servers, internal knowledge, persistent memory, databases, queues, and files.
Operate and improve	History, traces, costs, analytics, alerts, logs, and OpenTelemetry reveal runtime behavior. Evals support prompt and model iteration; access controls and human review shape how systems run.
Serve people and applications	REST and SSE endpoints, MCP tools, Portal conversations, Board jobs, and workflow-backed dashboards provide ways to invoke systems and use their results.

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✨ Key Capabilities

Build: Agents, Workflows, and Connected Tools

• Visual and AI-assisted authoring. Build and inspect workflow graphs on the canvas, generate or revise them through the AI Assistant using text or voice, and reuse templates.
• Agents and deterministic logic. Combine LLM and Agent nodes with conditions, switches, loops, merges, data transformations, and sub-workflow calls. Use expressions in supported node fields.
• Multi-agent orchestration. Give an orchestrator named sub-agents and sub-workflows to call. Independent sub-agent calls can execute concurrently.
• Knowledge and persistent memory. Retrieve documents through RAG using Qdrant or PostgreSQL with pgvector. Enable per-agent knowledge graphs to retain facts across runs, with configurable sharing between agents.
• Tools and integrations. Connect communication services, developer tools, productivity apps, databases, queues, and storage through built-in nodes, HTTP APIs, and MCP. Use MCP Call nodes for deterministic tool invocation.
• Skills and custom behavior. Attach reusable SKILL.md instructions and optional Python tools to agents, create or revise skills with AI, install plugins, or implement custom nodes with typed configuration and execution handlers.

Run: Execute and Coordinate Work

• Parallel execution and recovery. Run independent nodes concurrently, synchronize branches with Merge, and configure retries, backoff, error paths, and model fallback.
• Schedules and triggers. Start workflows through cron, webhooks, messaging integrations, inbox events, WebSocket messages, and Heym platform events.
• Browser and coding agents. Automate browser tasks with Playwright and AI-assisted selector recovery. Run Codex or OpenCode Go against a repository as workflow steps, with diff and pull-request outputs.
• Agentic Kanban Board. Cards are persistent agentic jobs. Moving a card into a column runs its ordered workflow chain with card content, comment