LightOS


LightOS is a proprietary mobile operating system developed by Light for its minimalist Light Phone series of mobile phones, including the Light Phone II and Light Phone III. It is an Android-based platform that uses a custom interface built with React Native. LightOS was developed in collaboration with the design agency Sanctuary Computer Inc., which joined Light in early 2018 to create the phone’s software stack. According to its developers, LightOS is the first operating system to embed a React Native application as the core UI launcher. The system is intentionally streamlined and designed to be used "as little as possible", providing only basic tools and eschewing the expansive app ecosystems of standard smartphones.

Overview

LightOS is the software platform running on Light's minimalist phones, which are often described as "anti-smartphones". It aims to offer only essential phone functions in order to reduce distractions and encourage intentional use of technology. The Light Phone II and III running LightOS can perform core tasks like calls and SMS texting, along with a handful of additional features referred to as "tools" rather than apps. The operating system does not support an app store or any third-party apps, and it omits services like web browsing, email and social media entirely. This minimalist philosophy is a deliberate design choice by Light; the company promotes LightOS as providing "just the tools you’ll need", with no infinite feeds, advertising, or addictive applications. In practice, LightOS devices are positioned as secondary phones or simplified primary phones for users seeking a digital detox or minimal connectivity.

Development

LightOS is built on the Android Open Source Project foundation. Specifically, the version running on the Light Phone II was forked from Android 8.1 Oreo, as that was the base OS provided for the phone's Qualcomm MSM8909 chipset. On top of the Android kernel and drivers, they implemented the user interface and native applications using React Native – a JavaScript web framework typically used for cross-platform app development. The React Native layer in LightOS is integrated as a platform-signed system application. This approach allowed the developers to more easily create a consistent UI and manage the unique demands of the phones' displays using declarative React components, rather than the imperative Android UI toolkit. Light’s co-founder has said that the decision to use React Native was driven by the need for a "reactive" and flexible rendering system to accommodate the slow refresh rate and ghosting issues inherent to e-ink displays. The operating system was primarily developed by Light’s in-house team in partnership with Sanctuary Computer, a software studio based in New York. Sanctuary joined the project in early 2018 to assist with system architecture and product development for the second Light Phone, contributing to the OS design, a custom online dashboard, and cloud infrastructure. The Light Phone 2 began shipping to backers in September 2019 with LightOS as its operating system. Development of LightOS has been continuous since launch, with the small Light team providing regular over-the-air software updates to add features and improve stability. In 2021, Light also released a software development kit and indicated interest in allowing third-party developers to create custom "tools" for the platform using React Native, though in practice LightOS remains a closed ecosystem and no public app store has been introduced.

Features

Because of its "tools, not apps" design ethos, LightOS includes only a limited selection of basic features. Out of the box, the phones provide calling and texting, along with a few simple built-in tools such as an alarm clock and a basic calculator. Over time, Light has added more optional tools that users can choose to enable. As of 2025, available tools on LightOS include:
Contacts and dialing – A phone app for calls, and a contacts directory.
Messages – SMS messaging interface. Picture messaging was initially absent but was introduced in a later LightOS update, allowing users to send photos via text.
Alarm/Timer – A simple alarm clock and a countdown timer tool.
Calculator – A basic calculator tool.
Notes/Voice memos – A note-taking tool that can also record voice memos.
Music player – A simple audio player for music files. Users can upload MP3s to the phone via the Light dashboard; streaming services are not supported.
Podcast player – An audio podcast tool that allows downloading episodes for offline listening.
Calendar – A simple calendar for events and reminders.
Maps – A navigation tool providing step-by-step directions. This tool uses a third-party mapping API to get location and route data, but it offers only text-based turn-by-turn directions or a minimal map, given the device’s simplified interface and e-ink display.
Hotspot – The ability to share the phone’s cellular data via Wi-Fi tethering.
All of these tools are written or configured by Light specifically for LightOS, and they can be added, removed, or re-ordered on the phone’s menu through a companion web interface. Each Light phone is linked to a web dashboard which users can log into from a computer or another device; from there, they can manage which tools are installed/enabled on their phone, import contacts, and adjust some settings remotely. This design — pushing most optional content management to the web portal — keeps the on-device software as simple as possible. For example, to add music or podcasts, a user must upload audio files or provide podcast RSS feeds via the dashboard; the phone then syncs the content. There is no on-device app installation or app store at all. Notably, LightOS supports fundamental smartphone capabilities under the hood, but many are not exposed to the user. It has support for LTE data, Wi-Fi and Bluetooth connectivity, and can interface with basic peripherals. However, typical smartphone features like web browsing, email, instant messengers, and social networking apps cannot run on LightOS unless the device is hacked by the user to bypass the default software. Advanced users have indeed found ways to "root" or unlock the Light Phone and access a more standard Android interface, but doing so is unofficial and not supported by Light.

Version history

Since its initial release on the Light Phone II, LightOS has seen a continuous progression of updates, delivered automatically to users via over-the-air updates. Light does not use conventional version numbers like "1.0" or "2.0" for public releases; instead, internal build numbers are used to denote updates. Major updates typically coincide with the introduction of new tools or hardware support, while smaller incremental patches address bug fixes and performance improvements. Light Phone II : The Light Phone II launched with a very limited feature set in 2019, initially supporting calls, texts, alarm, and hotspot. Through 2020 and 2021, LightOS updates expanded its functionality: for example, a simple calculator and notes app were added, followed by the release of a directions tool and a music player in subsequent updates. By mid-2021, the Light Phone II had gained a calendar tool and the ability to use podcasts, among other improvements. Development for the Light Phone II continued in the following years with refinements to the interface and quality-of-life features. In 2022–2023, Light shifted focus to preparing LightOS for the next device, while still issuing occasional patches and adding smaller features. Light Phone III : The Light Phone III, announced in mid-2024 and shipped in 2025, runs a newer iteration of LightOS adapted for its upgraded hardware. Light Phone III introduced a color 3.9-inch OLED display and added cameras, a fingerprint reader, and NFC capabilities for mobile payments. To support these, LightOS was updated with a simple camera application and an image gallery for viewing photos. However, some features were not fully ready at launch: for example, the fingerprint sensor on the Light Phone III shipped inactive, and the phone's NFC chip did not yet have an enabled payment tool initially. Light stated that these capabilities would be turned on in future software updates once the functionality was fully developed. Post-launch updates for Light Phone III have focused on optimizing the new display and camera features. LightOS on the Light Phone III continues to receive regular OTA updates, and the Light team has indicated that, as with the previous model, they will continue to refine the experience and possibly introduce a few additional tools over time.

Reception

LightOS and the Light Phone devices have drawn mixed reactions, reflecting a balance of appreciation for their focus and criticism of their limitations. The concept of a phone "designed to be used as little as possible" has been praised by those seeking minimalism and freedom from digital distraction. Wired described the Light Phone III’s experience as "stylish, well-made, fun to use" in its simplicity, calling it a "digital detox we need right now", and gave the device an 8/10 rating for fulfilling its niche. Time magazine honored the Light Phone II as one of the 100 Best Inventions of 2019, highlighting how it strips the smartphone to its essentials. Many users who adopted LightOS phones report positive lifestyle changes – for example, spending far less time on their phones each day – and value the intentional friction that the OS introduces to discourage mindless usage. On the other hand, reviewers often note that the extreme minimalism of LightOS can be a double-edged sword. While acknowledging the elegance of its design, Engadgets review of the Light Phone III commented that the device "can help you break your smartphone addiction, but it makes some major compromises" in functionality. Basic capabilities that users might take for granted even on feature phones – such as picture messaging, group texts, or a robust predictive keyboard – were missing or imperfect in early versions of LightOS, leading to frustration for some. For example, navigation on the Light Phone II was initially very limited and inaccurate, which critics pointed out could induce anxiety rather than alleviate it. The slow refresh rate of the e-ink screen on the Light Phone II made texting cumbersome for many users, and the absence of conveniences like voice assistants, maps with graphical interfaces, or any form of messaging beyond SMS meant the phone could feel "too limited" for everyday use by modern standards. Some reviewers and consumers have also been critical of the price point of Light's devices relative to their functionality. The Light Phone II retailed around $350 USD, and the Light Phone III launched at $599, which is comparable to mainstream smartphones that offer far more features and app ecosystems. This led some to argue the value proposition was poor – one commentator quipped that charging smartphone prices for a "dumb phone" was "actually criminal". Others, however, defend the pricing by pointing to the niche scale of production and the unique value it provides to those who truly need a distraction-free device. In summary, LightOS has been received as an intriguing experiment in reversing the trend of increasing smartphone complexity. It has a dedicated following among digital minimalists and those craving a simpler phone experience, and it has influenced broader conversations about "detoxing" from technology. At the same time, its practical trade-offs mean it remains a niche solution. As one review in The Verge noted, Light Phones "aren’t for everyone", but they offer a compelling alternative vision of what a mobile OS can be when "software intentionally does less, not more".