langchain-classic
Building applications with LLMs through composability
Decision gist · record as of 2026-08-14
Yes, but only if you are maintaining or migrating existing LangChain code. If starting a new project, use the main langchain package instead. The package is actively maintained, has no known vulnerabilities, and carries a permissive MIT license. Install friction is low and dependencies are stable.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later (up to <4.0.0).
- Intended for code that already depends on older LangChain APIs; new projects should use the main langchain package.
- Low friction install with a pure-Python wheel.
License · maintenance · safety
MIT (permissive) — MIT license permits commercial and private use with minimal restrictions—suitable for most production deployments.
last release 2026-06-10 (65 days) · last repo commit 2026-08-14 · 144,196 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 22,006,060 downloads/mo, #986 on PyPI
Alternatives
Verify before relying
pip install langchain-classic
from langchain_classic import chains
from langchain_classic.indexes import VectorstoreIndexCreator- Whether this package is necessary for new projects or only for migrating legacy code.
- Specific deprecation timeline and migration path for features in this package.
What it is and what it does
LangChain Classic is a compatibility layer that bundles legacy LangChain chains, re-exports from langchain-community, the indexing API, and deprecated functionality. It exists to support older LangChain applications that have not yet migrated to the current langchain package structure. The package depends on langchain-core, langchain-text-splitters, langsmith, pydantic, pyyaml, requests, sqlalchemy, and async-timeout, making it a bridge between older code and modern LangChain infrastructure.
Most new projects should use the main langchain package instead. This package is intended for teams maintaining existing LangChain applications or gradually migrating legacy code. It is actively maintained and supports Python 3.10 through 3.13.
Use it for
- Migrating older LangChain applications to a newer codebase without rewriting all chain definitions.
- Accessing community integrations and indexing APIs that have been moved or deprecated in the main package.
- Running legacy LangChain code in production while planning a longer-term upgrade path.
- Testing and monitoring legacy LangChain applications with LangSmith integration.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, but only if you are maintaining or migrating existing LangChain code.
If starting a new project, use the main langchain package instead. The package is actively maintained, has no known vulnerabilities, and carries a permissive MIT license. Install friction is low and dependencies are stable.
Install
langchain-classic on PyPI
Before you install
Low friction install with a pure-Python wheel. Active maintenance as of 65 days ago with a large community (144196 stars). Supports current Python versions (3.10–3.13).
Requires Python 3.10 or later (up to <4.0.0). Intended for code that already depends on older LangChain APIs; new projects should use the main langchain package.
License in practice
MIT license permits commercial and private use with minimal restrictions—suitable for most production deployments.
Quickstart
pip install langchain-classic
from langchain_classic import chains
from langchain_classic.indexes import VectorstoreIndexCreatorVerify before relying
- Whether this package is necessary for new projects or only for migrating legacy code.
- Specific deprecation timeline and migration path for features in this package.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release <4.0.0,>=3.10.0 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 8 packagesasync-timeoutlangchain-corelangchain-text-splitterslangsmithpydanticpyyamlrequestssqlalchemy |
| Maintenance | Actively maintained 65 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 22,006,060 / month, #986 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Topic :: Scientific/Engineering :: Artificial IntelligenceTopic :: Software Development :: Libraries :: Python Modules |
Evidence: langchain_classic-1.0.8-py3-none-any.whl
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See also langchain-community · langchain-core · langchain-openai · langchain-google-community · langchain-ollama · langchain · langchain-deepseek · langchain-xai · langserve · langchain-databricks