@meridian-agent/langgraph-checkpoint-cloudflare-d1

A LangGraph.js checkpoint saver backed by Cloudflare D1.

Use this when you are running LangGraph.js inside a Cloudflare Worker and want checkpoints stored in a D1 database through the Worker env.DB binding.

Installation

npm install @meridian-agent/langgraph-checkpoint-cloudflare-d1

You also need @langchain/langgraph-checkpoint in your project. This package is designed for Cloudflare Workers and expects a D1 binding.

Usage

Configure a D1 binding in wrangler.toml:

[[d1_databases]]
binding = "DB"
database_name = "langgraph-checkpoints"
database_id = "your-database-id"

Then create the saver from the Worker environment binding:

import { CloudflareD1Saver } from "@meridian-agent/langgraph-checkpoint-cloudflare-d1";

export interface Env {
  DB: D1Database;
}

export default {
  async fetch(_request: Request, env: Env): Promise<Response> {
    const checkpointer = new CloudflareD1Saver(env.DB);

    // Pass `checkpointer` to your LangGraph graph compile/configuration.
    // const app = graph.compile({ checkpointer });

    return new Response("OK");
  },
};

What It Stores

The saver creates two D1 tables automatically on first use:

• checkpoints
• writes

The schema and LangGraph-level behavior are based on the official SqliteSaver from @langchain/langgraph-checkpoint-sqlite, adapted for Cloudflare D1's async API.

Supported operations:

• getTuple(config)
• list(config, options)
• put(config, checkpoint, metadata)
• putWrites(config, writes, taskId)
• deleteThread(threadId)

Notes

• 0.0.4 — fix D1_TYPE_ERROR on first checkpoint of a thread (parent_checkpoint_id) and on putWrites with empty checkpoint_ns; coerce undefined to null/'' before bind().
• 0.0.3 — fix setup() crashing on Cloudflare D1 because db.exec() splits on newlines; switched to batch() with prepare().
• D1 is provided by Cloudflare through env.DB; there is no connection string helper.
• Setup is async and runs lazily before saver operations.
• Writes use db.batch() for multi-statement operations.
• SQL is SQLite-compatible and intended to run on Cloudflare D1.

Local Development

Install dependencies:

bun install

Typecheck:

bun run typecheck

Build:

bun run build

The build outputs ESM JavaScript and TypeScript declarations to dist.

Publishing

Before publishing, verify the package contents:

npm pack --dry-run

Publish publicly:

npm publish --access public