Jitsu: Open Source Integration Platforms

What is Jitsu?

Jitsu is an MIT-licensed, self-hostable open-source event data platform that collects events from websites, apps and servers and delivers them to data warehouses and other tools, built as a fully-scriptable alternative to Segment for data teams and developers who want the pipeline inside their own infrastructure.

What it is

Jitsu is an open-source event data platform and data ingestion engine written in TypeScript and released under the MIT licence. It lives in the Developer Tools and Integration Platforms category, and its stated purpose is to cover the same ground as Segment while remaining self-hostable, so the whole pipeline can run inside your own infrastructure or on Jitsu Cloud, which is the same software hosted. Events are collected from the browser, mobile apps, or the server through SDKs, an HTTP API, or a drop-in Segment proxy, and delivered to destinations including ClickHouse, BigQuery, Snowflake, Redshift, Postgres, S3, GCS and dozens of SaaS tools.

The concrete thing it replaces is Segment, and the concrete problem it solves is delivery latency and cost shape. Segment loads warehouses once or twice a day, hourly at best, while Jitsu delivers per destination in batches as frequent as a minute, or row by row where that suits the destination. Segment bills by Monthly Tracked User, whereas Jitsu Cloud bills by event volume, so the bill tracks data rather than audience size, and self-hosting carries no usage billing at all. Beyond event delivery, Jitsu also pulls data into the warehouse from third-party sources using Airbyte-compatible connectors.

Key capabilities

Event collection from the browser, mobile or server through the HTML snippet, @jitsu/js, @jitsu/jitsu-react, an HTTP API, or a drop-in Segment proxy.
Delivery to ClickHouse, BigQuery, Snowflake, Redshift, Postgres, S3, GCS and dozens of SaaS destinations, streamed or micro-batched depending on what the destination prefers.
Functions: JavaScript that runs on every event to filter, transform and enrich it before delivery.
The Jitsu CLI: jitsu-cli init scaffolds a TypeScript project with tests, and jitsu-cli deploy ships it to a workspace.
Connector syncs that pull data into the warehouse from third-party sources through Airbyte-compatible connectors.
A user identity graph and profile builder generated automatically from the event stream.
Live Events, which shows every event, function log and destination write as it happens, plus an MCP server and a Management API that mirror the UI.

Who uses it and how

Teams migrating off Segment without touching client code, by pointing existing clients at the Segment proxy.
Small teams starting on the Jitsu Cloud free tier of 200k events per month with no credit card, which includes a free ClickHouse instance plus custom domains, the events debugger and the Configuration API.
Self-hosters who need the entire pipeline to run inside their own infrastructure and want no usage billing at all.
Data teams that need events landing in the warehouse within a minute rather than on a daily or hourly schedule.
JavaScript and TypeScript developers who want to write functions in their own repository with their own test suite and CI, using the CLI rather than the browser editor.

Getting started

The fastest route named in the README is Jitsu Cloud at use.jitsu.com with a free tier of 200k events per month; after creating a workspace you create a site, take the write key, add a destination and start sending events. Self-hosting is documented separately for anyone who wants the same software on their own infrastructure.

How it compares

Against Segment, the only paid product named in the facts, Jitsu differs on licence, hosting and cost model. Jitsu is MIT-licensed and self-hostable end to end, so the data lands in a warehouse the operator controls, while self-hosting carries no usage billing. Jitsu Cloud then bills by event volume rather than by Monthly Tracked User, so the cost tracks the data rather than the size of the audience.

When to use it — and when not to

Choose it when the pipeline has to stay inside your own infrastructure, when event latency in the warehouse matters, or when per-MTU pricing is the wrong shape for the workload. A self-hoster takes on operating the ingestion service itself and the destinations it writes to, so a team with no appetite for running infrastructure should use Jitsu Cloud or stay on a managed SaaS. The README excerpt is explicit about destinations and SDKs but does not document the backing services a self-hosted install requires, so that work should be scoped against the self-hosting docs before committing.

project readme (upstream, from github) — read inline

Open-source event data platform. An alternative to Segment.

Website · Docs · MCP Server · Jitsu Cloud · Self-hosting · Slack · MIT License

What is Jitsu?

Jitsu collects event data from your websites, apps and servers, and delivers it to your data warehouse and to whatever other tools you use. It covers the same ground as Segment, but it's MIT-licensed and self-hostable, so the whole pipeline can run inside your own infrastructure — or on Jitsu Cloud, same software, hosted.

Data lands in minutes, not hours: Segment loads warehouses once or twice a day (hourly at best), while Jitsu delivers per destination in batches as frequent as a minute, or row-by-row where that suits the destination. And where Segment bills by Monthly Tracked User, Jitsu Cloud bills by event volume, so the bill tracks data rather than audience size — while self-hosting has no usage billing at all.

A typical Jitsu setup gives you:

Event collection from the browser, mobile, or the server, via SDKs, an HTTP API, or a drop-in Segment proxy.
Delivery to destinations — ClickHouse, BigQuery, Snowflake, Redshift, Postgres, S3, GCS, and dozens of SaaS tools, streamed or micro-batched depending on what the destination prefers. See the destination catalog.
Functions — JavaScript that runs on every event to filter, transform, and enrich it before delivery.
- Write them in the browser, or build and deploy them from your own repo with the Jitsu CLI — jitsu-cli init scaffolds a TypeScript project with tests, and jitsu-cli deploy ships it to your workspace. Use whatever tooling you like: TypeScript, npm libraries, your own test suite, and your normal CI.
Connector syncs — pull data into your warehouse from third-party sources (Airbyte-compatible connectors).
A user identity graph and profile builder, built automatically from the event stream.
Live Events — see every event, function log and destination write as it happens, which makes debugging a pipeline a matter of seconds rather than days.
An MCP server, so an AI agent can configure and operate all of the above.

Get started with Jitsu Cloud

The fastest way to run Jitsu is Jitsu Cloud — we host and scale it for you.

Free tier: 200k events/month, no credit card required.
Unlimited destinations and unlimited captured events on every plan.
A free ClickHouse instance is included, so you can go from zero to queryable event data without provisioning a warehouse first.
Custom domains, events debugger, and the Configuration API on the free tier too.

See pricing for the full breakdown, or jump straight into the Quick Start guide.

Once you have a workspace:

Create a site (a stream) and grab your write key.
Add a destination — ClickHouse, BigQuery, Snowflake, Postgres, S3, or anything from the catalog.
Start sending events using one of the methods below.

Sending events

Method	Use it for
HTML snippet	Any website, no build step
`@jitsu/js`	Isomorphic — works in the browser and in Node.js
`@jitsu/jitsu-react`	React and Next.js apps
HTTP API	Any language, backend services
Segment proxy	Migrating off Segment without touching client code

Everything the UI does is also available through the Management API and the Jitsu CLI.

Jitsu MCP Server

Jitsu ships a Model Context Protocol server, so coding agents and AI assistants can build and operate your data pipelines directly — no clicking through the UI.

An agent connected to Jitsu can set up a destination, wire a connection, send a test event, read the resulting Live Events, notice that a function threw, fix the function, and re-run it — the full loop, without a human in the middle.

Endpoint: https://use.jitsu.com/mcp (or /mcp when self-hosting).

Connect your client

Claude Code

claude mcp add --transport http jitsu https://use.jitsu.com/mcp

Other clients (Claude Desktop, Cursor, VS Code) take the same URL — see jitsu.com/docs/mcp for their setup.

Authentication

Interactive clients use OAuth 2.1 — no API key to manage. The first tool call opens a browser tab asking you to approve the connection; tokens are scoped, listed, and revocable from your account settings page.

Headless environments (CI, cron, servers) use a personal API key instead — generate one on the user settings page and pass it as Authorization: Bearer ::

claude mcp add --transport http jitsu https://use.jitsu.com/mcp \
  --header "Authorization: Bearer $JITSU_API_KEY"

What the agent can do

25 tools, covering everything the console does: read and write workspace configuration (destinations, streams, connections, functions), query Live Events and function logs, run and cancel connector syncs, discover source streams and inspect sync state, execute functions and profile builders against test data, and pull event and sync statistics. Full reference: jitsu.com/docs/mcp.

Architecture

Jitsu is a handful of independently scalable services:

Service	Stack	What it does
ingest	Go	HTTP endpoint that accepts events and writes them to Kafka
rotor	TypeScript	Routes events, runs Functions, applies destination-specific transforms
bulker	Go	High-throughput warehouse ingestion — batching, schema management, retries
sync-controller	Go	Orchestrates connector syncs (pulling data from third-party sources)
console	Next.js	Admin UI, Management API, and the MCP server

Backed by Postgres (configuration), Kafka/Redpanda (event bus), ClickHouse (live events and metrics), and MongoDB (profiles).

Bulker is also usable standalone if you just want a warehouse ingestion engine and are comfortable with low-level APIs.

Self-hosting

Jitsu is MIT-licensed and fully self-hostable, with no usage limits and no feature gating. Cloud is the path of least resistance; self-hosting is for when you need the data to stay inside your ow

Frequently asked questions

Is Jitsu free to use?

Jitsu is open source under the MIT licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does Jitsu do?

Open-source data integration for modern stacks

What is Jitsu written in?

Jitsu is primarily written in TypeScript. Its source is publicly available at https://github.com/jitsucom/jitsu, and it has 5,083 GitHub stars.