Source: https://seerepo.com/r/langchain-ai/langchainjs/built
Markdown source: https://seerepo.com/r/langchain-ai/langchainjs/built.md
Description: langchainjs is a TypeScript repo built with Express and Hono. It stores its data in bson, @pinecone-database/pinecone, and weaviate-client.

# What is langchainjs built with?

langchainjs is a TypeScript repo built with Express and Hono. It stores its data in bson, @pinecone-database/pinecone, and weaviate-client, reaches it with TypeORM, signs people in with @aws-sdk/credential-provider-node, jose, and @azure/identity, uses AI through langsmith, js-tiktoken, @langchain/langgraph, langchain, aws-sdk, and 3 more, makes its content with Cheerio, handlebars, js-yaml, yaml, and mustache, validates its data with Zod, validate-npm-package-name, @cfworker/json-schema, and @standard-schema/spec, is tested with Vitest, Jest, jest-environment-node, testcontainers, and Faker, deploys with @hono/node-server and @aws-sdk/types, and uses MCP. It has 446,312 written lines, with 761 test files.

Read on November 6, 2026, at commit 8103487.

Repository: https://github.com/langchain-ai/langchainjs

## Support (internal/model-profiles)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 2 files

### Tools

- **commander**: 1 file
- **oxfmt**: 1 file
- **TypeScript**: 1 file

### Other

- **@iarna/toml**: 1 file

## Frontend (libs/create-langchain-integration)

### Interface

- **[prompts](https://seerepo.com/uses/prompts)**: 1 file

## Support (libs/create-langchain-integration)

### Validation

- **validate-npm-package-name**: 1 file

### Tools

- **commander**: 1 file
- **fast-glob**: 1 file
- **update-check**: 1 file

### Other

- **picocolors**: 3 files
- **conf**: 1 file

## Support (libs/create-langchain-integration/template)

### Testing

- **Jest**: 4 files
- **jest-environment-node**: 1 file

## Backend (libs/langchain-classic)

### Data access

- **TypeORM**: 2 files

### AI

- **langsmith**: 3 files

## Support (libs/langchain-classic)

### Content

- **[Cheerio](https://seerepo.com/uses/cheerio)**: 1 file
- **[handlebars](https://seerepo.com/uses/handlebars)**: 1 file
- **[js-yaml](https://seerepo.com/uses/js-yaml)**: 1 file
- **[yaml](https://seerepo.com/uses/yaml)**: 1 file

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 7 files

### Testing

- **Vitest**: 115 files

### Tools

- **openapi-types**: 2 files
- **peggy**: 1 file

## Backend (libs/langchain-core)

### AI

- **langsmith**: 9 files
- **js-tiktoken**: 2 files

## Support (libs/langchain-core)

### Content

- **[mustache](https://seerepo.com/uses/mustache)**: 1 file

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 34 files
- **@cfworker/json-schema**: 3 files
- **[@standard-schema/spec](https://seerepo.com/uses/standard-schema-spec)**: 3 files

### Testing

- **Vitest**: 105 files

### Other

- **p-queue**: 2 files
- **web-streams-polyfill**: 1 file

## Backend (libs/langchain-mcp-adapters)

### The base

- **[Express](https://seerepo.com/uses/express)**: 2 files

### AI

- **@langchain/langgraph**: 3 files

### Services

- **[MCP](https://seerepo.com/uses/mcp)**: 8 files · [libs/langchain-mcp-adapters/src/client.ts, line 12](https://github.com/langchain-ai/langchainjs/blob/8103487c55784c5befd84c1bc803546f720f806e/libs/langchain-mcp-adapters/src/client.ts#L12)

## Support (libs/langchain-mcp-adapters)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 7 files

### Testing

- **Vitest**: 18 files

## Backend (libs/langchain-textsplitters)

### AI

- **js-tiktoken**: 1 file

## Support (libs/langchain-textsplitters)

### Testing

- **Vitest**: 2 files

## Backend (libs/langchain)

### AI

- **[langchain](https://seerepo.com/uses/langchain)**: 22 files
- **langsmith**: 3 files

## Support (libs/langchain)

### The base

- **[Hono](https://seerepo.com/uses/hono)**: 1 file

### Content

- **[yaml](https://seerepo.com/uses/yaml)**: 1 file

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 16 files

### Testing

- **Vitest**: 86 files

### Deploy

- **[@hono/node-server](https://seerepo.com/uses/hono-node-server)**: 1 file

### Tools

- **tinybench**: 1 file

## Support (libs/providers/langchain-anthropic)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 2 files

### Testing

- **Vitest**: 34 files

## Backend (libs/providers/langchain-aws)

### Sign-in

- **@aws-sdk/credential-provider-node**: 1 file

### AI

- **[aws-sdk](https://seerepo.com/uses/aws-sdk)**: 10 files

## Support (libs/providers/langchain-aws)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 3 files

### Testing

- **Vitest**: 10 files
- **Jest**: 2 files

### Deploy

- **@aws-sdk/types**: 1 file

### Other

- **@smithy/types**: 4 files

## Support (libs/providers/langchain-cloudflare)

### Testing

- **Vitest**: 5 files

### Tools

- **Cloudflare**: 4 files

## Backend (libs/providers/langchain-cohere)

### AI

- **cohere-ai**: 5 files

## Support (libs/providers/langchain-cohere)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 7 files

## Support (libs/providers/langchain-deepseek)

### Testing

- **Vitest**: 3 files

## Support (libs/providers/langchain-exa)

### Testing

- **Vitest**: 3 files

### Other

- **exa-js**: 2 files

## Support (libs/providers/langchain-fireworks)

### Testing

- **Vitest**: 5 files

## Support (libs/providers/langchain-google-common)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 3 files

### Testing

- **Vitest**: 8 files

## Support (libs/providers/langchain-google-gauth)

### Testing

- **Vitest**: 3 files

## Support (libs/providers/langchain-google-genai)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 4 files

### Testing

- **Vitest**: 11 files

## Support (libs/providers/langchain-google-vertexai-web)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 6 files

## Support (libs/providers/langchain-google-vertexai)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 6 files

## Support (libs/providers/langchain-google-webauth)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Jest**: 3 files
- **jest-environment-node**: 1 file

## Backend (libs/providers/langchain-google)

### Sign-in

- **[jose](https://seerepo.com/uses/jose)**: 1 file

## Support (libs/providers/langchain-google)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 4 files

### Testing

- **Vitest**: 15 files

### Other

- **eventsource-parser**: 2 files

## Backend (libs/providers/langchain-groq)

### AI

- **groq-sdk**: 1 file

## Support (libs/providers/langchain-groq)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 2 files

### Testing

- **Vitest**: 5 files

## Support (libs/providers/langchain-ibm)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 12 files

## Support (libs/providers/langchain-mistralai)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 1 file

### Testing

- **Vitest**: 7 files

## Backend (libs/providers/langchain-mongodb)

### Data

- **bson**: 2 files

## Support (libs/providers/langchain-mongodb)

### Testing

- **Vitest**: 9 files
- **testcontainers**: 1 file

### Other

- **SemVer**: 1 file

## Support (libs/providers/langchain-neo4j)

### Testing

- **Vitest**: 7 files

## Backend (libs/providers/langchain-ollama)

### AI

- **[ollama](https://seerepo.com/uses/ollama)**: 4 files

## Support (libs/providers/langchain-ollama)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 3 files

### Testing

- **Vitest**: 12 files

## Backend (libs/providers/langchain-openai)

### Sign-in

- **[@azure/identity](https://seerepo.com/uses/azure-identity)**: 2 files

### AI

- **js-tiktoken**: 2 files

## Support (libs/providers/langchain-openai)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 5 files

### Testing

- **Vitest**: 49 files

## Support (libs/providers/langchain-openrouter)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 2 files

### Testing

- **Vitest**: 7 files

### Other

- **eventsource-parser**: 2 files

## Support (libs/providers/langchain-perplexity)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 2 files

### Testing

- **Vitest**: 9 files

## Support (libs/providers/langchain-pgvector)

### Testing

- **Vitest**: 1 file

## Backend (libs/providers/langchain-pinecone)

### Data

- **@pinecone-database/pinecone**: 3 files

## Support (libs/providers/langchain-pinecone)

### Testing

- **Vitest**: 7 files
- **Faker**: 1 file

### Other

- **flat**: 1 file

## Support (libs/providers/langchain-qdrant)

### Testing

- **Vitest**: 2 files
- **Faker**: 1 file

## Support (libs/providers/langchain-redis)

### Testing

- **Vitest**: 5 files
- **Faker**: 1 file

## Support (libs/providers/langchain-tavily)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 6 files

### Testing

- **Vitest**: 10 files

## Support (libs/providers/langchain-together-ai)

### Testing

- **Vitest**: 7 files

## Support (libs/providers/langchain-typesafe)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 5 files

### Testing

- **Vitest**: 16 files

## Backend (libs/providers/langchain-weaviate)

### Data

- **weaviate-client**: 2 files

## Support (libs/providers/langchain-weaviate)

### Testing

- **Vitest**: 5 files

### Other

- **.ENV**: 3 files

## Support (libs/providers/langchain-xai)

### Validation

- **[Zod](https://seerepo.com/uses/zod)**: 2 files

### Testing

- **Vitest**: 15 files

## Other repos with a similar stack

- [RocketChat/Rocket.Chat](https://seerepo.com/r/RocketChat/Rocket.Chat/built): Express, Hono, bson, Zod, Cheerio, @hono/node-server, aws-sdk, jose · [Compare](https://seerepo.com/compare/langchain-ai/langchainjs/vs/RocketChat/Rocket.Chat)
- [novuhq/novu](https://seerepo.com/r/novuhq/novu/built): Express, MCP, Hono, Zod, prompts, validate-npm-package-name, handlebars, aws-sdk · [Compare](https://seerepo.com/compare/langchain-ai/langchainjs/vs/novuhq/novu)
- [CopilotKit/CopilotKit](https://seerepo.com/r/CopilotKit/CopilotKit/built): Express, MCP, Hono, Zod, @cfworker/json-schema, @standard-schema/spec, @hono/node-server, groq-sdk · [Compare](https://seerepo.com/compare/CopilotKit/CopilotKit/vs/langchain-ai/langchainjs)
- [ruvnet/ruflo](https://seerepo.com/r/ruvnet/ruflo/built): Express, MCP, Zod, handlebars, js-yaml, yaml, jose · [Compare](https://seerepo.com/compare/langchain-ai/langchainjs/vs/ruvnet/ruflo)
- [mem0ai/mem0](https://seerepo.com/r/mem0ai/mem0/built): @pinecone-database/pinecone, weaviate-client, Zod, cohere-ai, groq-sdk, ollama, @azure/identity · [Compare](https://seerepo.com/compare/langchain-ai/langchainjs/vs/mem0ai/mem0)
- [Mintplex-Labs/anything-llm](https://seerepo.com/r/Mintplex-Labs/anything-llm/built): Express, MCP, @pinecone-database/pinecone, weaviate-client, Cheerio, js-tiktoken, ollama · [Compare](https://seerepo.com/compare/langchain-ai/langchainjs/vs/Mintplex-Labs/anything-llm)

## Frequently asked questions

### What language is langchainjs written in?

langchainjs is written in TypeScript, with 446,312 written lines.

### What framework does langchainjs use?

langchainjs is built with Express and Hono.

### What database does langchainjs use?

langchainjs stores its data in bson, @pinecone-database/pinecone, and weaviate-client and reaches it with TypeORM.

### What does langchainjs sign people in with?

langchainjs signs people in with @aws-sdk/credential-provider-node, jose, and @azure/identity.

### Does langchainjs use AI?

Yes. langchainjs uses AI through langsmith, js-tiktoken, @langchain/langgraph, langchain, aws-sdk, cohere-ai, groq-sdk, and ollama.

### What services does langchainjs use?

langchainjs uses MCP.

The proof: [libs/langchain-mcp-adapters/src/client.ts, line 12](https://github.com/langchain-ai/langchainjs/blob/8103487c55784c5befd84c1bc803546f720f806e/libs/langchain-mcp-adapters/src/client.ts#L12)

### Does langchainjs have tests?

Yes. langchainjs has 761 test files and is tested with Vitest, Jest, jest-environment-node, testcontainers, and Faker.

### Which repos have a stack like langchainjs's?

The ones that share most of its stack: RocketChat/Rocket.Chat, novuhq/novu, and CopilotKit/CopilotKit.

## What is your repo built with?

Any public repo, with no account: https://seerepo.com/r/owner/repo/built, with the owner and name it has on GitHub.