Manifest V3 builds
Extensions built for how Chrome works now — service workers, declarative permissions scoped tight, and state kept in storage so nothing dies when the worker sleeps.
Web · Extensions
Chrome extension development — MV3 extensions we ship ourselves
We build Manifest V3 Chrome extensions — and we run two of our own in the Web Store: Redkit, which exports Reddit chat conversations, and Upwora, an AI co-pilot for Upwork freelancers. Every trap in this platform, we have already hit on our own products.
MV3
Manifest V3, service workers
2 shipped
our own extensions, live
Web Store
submission & review handled
Most extension bugs come from a service worker that went to sleep.
Manifest V3 killed the long-lived background page, so your worker is now killed and restarted whenever Chrome feels like it — and code that assumed a running process quietly falls over. We build around that reality, and we know it works because our own two extensions ship on top of it every day.
What we build
The parts that decide whether it works.
Content scripts & messaging
Content scripts that read and change the pages your users are on without clashing with the site, wired to the worker through reliable message passing — the part that breaks in careless extensions.
Web Store submission
We handle the listing, permission justifications, privacy disclosures and the reviewer back-and-forth — scoping permissions tight so it clears review fast and users trust the install prompt.
V2 to V3 migration
We port dead Manifest V2 extensions to V3 — background page to service worker, deprecated APIs replaced, and tested so nothing silently breaks when the worker restarts.
How we work
Scoped, shipped weekly, handed over clean.
01
Scope the extension
We map what it does on which pages, which permissions it truly needs, and where the Web Store will scrutinise it — with a fixed estimate before any code.
02
Build & test in Chrome
Working software each week loaded in a real browser, tested against the actual sites and the service-worker lifecycle — not just a happy-path demo.
03
Submit & support
We get it through Web Store review, hand over readable code your team can own, and are still here when Chrome changes something under you.
Where it fits
What teams hire us to build.
- A productivity tool that lives on top of a site users already use
- An AI co-pilot injected into a web app, the way Upwora works
- Exporting or capturing data from a site, the way Redkit does
- An internal extension for your team workflow
- Migrating an old Manifest V2 extension to V3
- A companion extension for your existing SaaS product
Questions
What clients ask before we start.
Have you actually shipped a Chrome extension, or just built them for clients?
Both — and the first matters more. We build and ship two of our own Manifest V3 extensions: Redkit, which exports Reddit chat conversations, and Upwora, an AI co-pilot for Upwork freelancers. Every problem you will hit — service worker lifecycles, Web Store review, content-script clashes — we have already hit in production on our own dime.
Do you build on Manifest V3?
Only V3 — V2 is dead and Chrome is removing it. That means service workers instead of background pages, declarative permissions, and the message-passing patterns that keep an ephemeral worker from dropping state. It is a real shift, and a lot of tutorials still teach the old way. We build for how the platform works now.
Can you migrate our old Manifest V2 extension to V3?
Yes, and it is more than a config change. The background page becomes a service worker that Chrome kills and restarts, so any code that assumed a long-lived process has to be reworked around events and storage. We port the logic, replace the deprecated APIs, and test that nothing silently breaks when the worker sleeps — then get it back through review.
How does Chrome Web Store submission work?
We handle it — the listing, the permission justifications, the privacy disclosures, and the back-and-forth if a reviewer pushes back. The common rejection is asking for broad permissions you do not need, so we scope permissions tight from the start. That is faster through review and it is what users trust when they read the install prompt.
Will it work in Edge or Firefox too?
Edge runs the same Chromium extension almost as-is, so that is nearly free. Firefox uses a compatible but not identical WebExtensions API, so a cross-browser build takes deliberate work — we tell you upfront what shares code and what needs a separate path, instead of promising "write once, run everywhere" and quietly breaking on one.
Related services
Further reading