Immer by immerjs
Create the next immutable state by mutating the current one
About Immer
From the project's README at github.com/immerjs/immer. Lightly cleaned for readability; for the full source see the upstream repo.
[](https://www.npmjs.com/package/immer) [](https://github.com/immerjs/immer/actions?query=branch%3Amain) [](https://coveralls.io/github/immerjs/immer?branch=main) [](https://github.com/prettier/prettier) [](#backers) [](#sponsors) [](https://gitpod.io/#https://github.com/immerjs/immer)
Create the next immutable state tree by simply modifying the current tree
Winner of the "Breakthrough of the year" React open source award and "Most impactful contribution" JavaScript open source award in 2019 Contribute using one-click online setup
You can use Gitpod (a free online VSCode like IDE) for contributing online. With a single click it will launch a workspace and automatically: clone the immer repo. install the dependencies. run .
Health score breakdown
6-dimension composite. See methodology for formula and weights.
Adoption signals
Real-world usage data, pulled from each registry. The bigger the numbers, the more battle-tested the project.
| Signal | Value | Source |
|---|---|---|
| GitHub stars | 29k | github.com/immerjs/immer |
| GitHub forks | 868 | github.com/immerjs/immer |
| NPM downloads (last month) | 198726k | immer |
Release & maintenance
Is this project actively maintained, or about to die? Check the recency of last commit and last release.
| Project age | 8.4 years | since Dec 2017 |
| Last commit | 3 days ago | May 4, 2026 |
| Releases shipped | 120 | last: 3 days ago |
| Security policy | SECURITY.md | declared by maintainers |
| Funding links | 3 | declared by maintainers |
Self-hosting cost across providers
Detected requirements: 4GB RAM, 40GB disk minimum. Cheapest plan per provider that meets the requirement.
| Provider | Plan | Specs | Monthly | |
|---|---|---|---|---|
| hetzner | CAX11 | 2c · 4GB · 40GB | $4.13 USD | Deploy → |
| vultr | VC2 | 1c · 1GB · 25GB | $5 USD | Deploy → |
| linode | Nanode 1GB | 1c · 1GB · 25GB | $5.12 USD | Deploy → |
| digitalocean | Basic Regular 1GB | 1c · 1GB · 25GB | $6 USD | Deploy → |
Security advisories
GHSA-c36v-fmgq-m8hx. What people say on Hacker News
Ready to self-host Immer?
Spin up a hetzner CAX11 (4GB RAM, 40GB disk) for $4.13/mo and follow the project's official install docs.
Data last refreshed May 7, 2026.
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