head to head · open source
Langflow vs validator
Langflow has 155,507 GitHub stars, 10,180 forks, 1,056 open issues and last shipped today. validator has 1,988 stars, 336 forks, 0 open issues and last shipped 3 days ago. Langflow leads on adoption by 7,722% (155,507 vs 1,988 stars). Langflow is written in Python under MIT; validator is written in Java under MIT. Langflow has attracted 7% as many forks as stars, validator 17%. Langflow was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Langflow | validator | |
|---|---|---|
| GitHub stars | ★ 156K | ★ 2.0K |
| License | MIT | MIT |
| Written in | Python | Java |
| Last push | 2026-10-05 | 2026-10-02 |
| Forks | ⑂ 10K | ⑂ 336 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Langflow if
- You weight community size — 156K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick validator if
- You want the validator feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Java
- You evaluated both and validator fits your workflow better
About Langflow
Langflow is a visual builder platform for designing, testing, and deploying AI agents and retrieval augmented generation (RAG) pipelines. It lives in the Python based generative AI ecosystem and targets developers building intelligent applications. The project provides a low code interface to assemble components—such as LLMs, vector stores, memory modules, and tools—into executable workflows, while also exposing those workflows as APIs or MCP servers for integration into external applications.
read the full Langflow overview →
About validator
The Nu Html Checker (vnu) is an MIT licensed Java tool and HTTP service for catching mistakes in HTML, CSS, and SVG documents, aimed at developers who want command line, scripted, or self hosted web standards validation.
read the full validator overview →
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Frequently asked questions
Is Langflow or validator more popular?
Langflow has 155,507 GitHub stars and validator has 1,988. Langflow has the larger community by that measure.
Are Langflow and validator free?
Both are open source. Langflow is licensed under MIT and validator under MIT. Neither carries a licence fee.
What is the difference between Langflow and validator?
Langflow is written in Python and validator in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Langflow or validator?
Choose Langflow if you want the larger community (155,507 stars) or its MIT licence terms. Choose validator if its feature set, stack or MIT licence fits better. Both are self-hostable.