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Langflow vs Prompt Declaration Language: catalog facts
Langflow	Prompt Declaration Language
Free Free and open source under the MIT license.	Free Free to use; model providers it calls may charge separately.
Web, Self-hosted	macOS, Command line
Visual canvas plus built-in API and MCP server output Supports a large library of LLMs, vector databases and tools	Prompts written as declarative YAML with enforced structure Not tied to a particular programming language
Requires separate access to whichever LLM providers or local models you connect Complex workflows can require developer-level setup	Requires learning a new YAML-based language Aimed at developers rather than everyday AI users
Self-hosted, Web application	Downloadable app
Open source	Closed source
License: MIT	License not stated
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 22, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.