8 Best ChainForge Alternatives in 2026 (Open Source)
ChainForge — An open-source visual programming environment for battle-testing prompts to LLMs. vs PromptFoo/LangSmith: visual data-flow environment for prompt engineering with built-in cross-model comparison, permutation testing, and statistical visualization
Short answer
- Closest match to ChainForge: Promptfoo.
- Most actively developed: Agenta (8,921 commits in the last 90 days).
- Fastest growing: Langfuse (+1,807 GitHub stars in the last 30 days).
- No commit in 6+ months: iX.
These 8 open-source tools do the same job. They are ordered by how closely they match ChainForge, with live GitHub data so you can see which projects are actively maintained.
By package downloads Langfuse is the most used here (22.4M in the last 30 days), even though Langflow has the most GitHub stars. See all agent tools by downloads.
| Tool | GitHub stars | Stars / 30d | Last commit | Downloads / 30d |
|---|---|---|---|---|
| ChainForge(original) | 3.0k | +11 | 2026-10-02 | 2.6K |
| Promptfoo | 25.7k | +1,110 | 2026-10-02 | 3.0M |
| Langflow | 155.5k | +1,446 | 2026-10-01 | 40.1K |
| Langfuse | 35.3k | +1,807 | 2026-10-02 | 22.4M |
| phoenix | 11.7k | +415 | 2026-10-03 | 645.6K |
| Agenta | 4.8k | +129 | 2026-10-02 | 13.9K |
| langwatch | 4.9k | +275 | 2026-10-02 | 1.9K |
| OpenLIT | 2.8k | +77 | 2026-10-01 | 287.2K |
| iX | 1.0k | 0 | 2024-03-03 | — |
1. Promptfoo
Open-source CLI and library for evaluating and red-teaming prompts, agents, RAG systems, and LLM apps
What sets it apart: Unlike LangSmith (production observability) or Langfuse (logging), promptfoo is the only open-source tool combining eval + red teaming + CI/CD code scanning — now backed by OpenAI while remaining fully MIT-licensed
Best for: Teams hardening LLM apps against prompt injection and jailbreaks with automated red teaming; Engineering teams adding LLM eval regression tests to CI/CD pipelines
2. Langflow
Langflow is a powerful tool for building and deploying AI-powered agents and workflows.
What sets it apart: Best visual builder for LLM workflows with direct MCP server deployment — more production-ready than Flowise with API-first architecture
Best for: Rapid prototyping of AI agent workflows with visual builder; Non-developers building LLM applications without coding
3. Langfuse
Open-source LLM engineering platform for observability, evaluation, prompt and dataset management
What sets it apart: Unlike LangSmith (LangChain-specific) or Helicone (proxy-based), Langfuse is fully open-source, framework-agnostic, and self-hostable, combining tracing, prompt management, evaluations, and datasets in a single platform built on ClickHouse for scalable production use.
Best for: Teams operating production LLM applications who need tracing, prompt management, and evaluation in one platform; Organizations requiring self-hosted LLM observability for data privacy compliance
4. phoenix
AI Observability & Evaluation
What sets it apart: Full-stack AI observability (tracing + eval + datasets + prompt management) in one open-source platform — vs LangSmith which is closed-source and LangChain-specific
Best for: Debugging and monitoring LLM applications in production; Systematic prompt engineering and experiment tracking
5. Agenta
The open-source LLMOps platform: prompt playground, prompt management, LLM evaluation, and LLM observability all in one place.
What sets it apart: Unified open-source LLMOps platform combining prompt playground, version control, 20+ evaluators, and OTel-native observability in one tool — vs separate tools for each
Best for: Teams needing integrated prompt management + evaluation + observability; Product teams collaborating with SMEs on prompt engineering; Organizations wanting open-source LLMOps alternative
6. langwatch
The platform for LLM evaluations and AI agent testing
What sets it apart: Unified platform combining agent simulation, evaluation, observability, and prompt optimization with OpenTelemetry-native design — vs separate tools for tracing (Langfuse), eval (DeepEval), and prompt management
Best for: Teams wanting eval + observability + prompt management in one tool; Agent simulation testing before production deployment; Organizations needing OpenTelemetry-native LLM observability
7. OpenLIT
Open-source platform for AI agent tracing, evaluations, guardrails, prompts, and GPU monitoring
What sets it apart: Most comprehensive open-source AI engineering platform — combines observability, 11 evaluation types, rule engine, prompt hub, secret vault, playground, and fleet management in one tool
Best for: Teams wanting all-in-one LLM platform (observability + eval + prompts + secrets); Organizations needing self-hosted AI engineering platform; Multi-language teams (Python/TS/Go SDK support)
8. iX
Autonomous GPT-4 agent platform
What sets it apart: vs LangChain/AutoGen: visual no-code drag-and-drop editor with native multi-agent orchestration and horizontal worker scaling — design complex agent workflows visually instead of writing code
Best for: Building custom multi-agent teams with visual no-code editor; Rapid prototyping of AI workflows without coding; Organizations needing self-hosted parallel agent execution at scale
FAQ
- What are the best alternatives to ChainForge?
- The closest open-source alternatives to ChainForge are Promptfoo, Langflow and Langfuse, followed by phoenix, Agenta and langwatch. They are ranked by how closely they match what ChainForge does.
- Which ChainForge alternative is the most popular?
- Langflow has the most GitHub stars among ChainForge alternatives, with 155,471 stars.
- Which ChainForge alternative is the most actively maintained?
- By recent activity, Agenta (8,921 commits in the last 90 days) is the most actively developed alternative.
Maintain ChainForge or one of these alternatives?
Each tool page has a maintainer box: a README badge with your live rank and stars, or a homepage + category feature for $49 / 7 days.
ChainForge · Promptfoo · Langflow · Langfuse · phoenix · Agenta