Chrome extension development from a team that ships its own
Whether you want to turn a repetitive task into one click, bring your product into the pages your users already work in, or launch an extension people pay for, we build your Chrome extension from start to finish. Weras Labs builds, publishes and sells its own Chrome extension, HookSlayer, on the Chrome Web Store. We know Manifest V3, the store review process and the practical side of making money from an extension firsthand.
What kind of browser extensions we build
A Chrome extension is powerful because it runs inside the pages your users already have open. The extensions we build most often:
- Productivity extensions: form filling, collecting data from pages, one-click saving and automating repetitive steps.
- A browser companion for your product: side panels and buttons that bring your SaaS into Gmail, LinkedIn or any other site.
- AI-powered extensions: summarising selected text, drafting replies or analysing page content.
- Internal extensions: private extensions distributed only to your team and connected to your internal systems.
- Commercial extensions: free and paid plans with licence checks and payments.
Extensions we build for Chrome usually run on Edge, Brave and Opera with minor changes, and we can prepare a Firefox build when you need it.
What shipping our own extension taught us
Building HookSlayer surfaced the same issues you will face in your project:
- Manifest V3: service workers instead of background pages, no remotely hosted code and new network rules. We design for these from day one.
- Store review: permission justifications, a privacy policy, data-use disclosures and the usual rejection reasons. Asking only for the permissions you need shortens review.
- Payments and licensing: the Chrome Web Store no longer processes payments, so paid extensions need an external payment provider and licence verification.
- Updates: resilient selectors and error monitoring, so the extension keeps working when target sites change their layout.
That experience means an extension that gets approved first time and that users trust enough to install.
What affects cost and timeline
Cost depends on how many sites the extension works on and how deeply, whether it needs a backend, user accounts and payments, AI features and support for multiple browsers.
As a rough guide, a focused single-purpose extension takes 2–4 weeks, and a commercial extension with accounts, payments and a backend takes 6–10 weeks. Store review usually takes a few days, and we plan for it.
Describe your extension idea in a few sentences and we will send a free quote with scope and timeline. To fit your budget, we can launch the core feature first and grow it with user feedback.
Technology
- Extension: TypeScript and React for the popup, side panel and options page, built on Manifest V3
- Backend: Node.js APIs, Firebase for accounts and storage, hosted on Vercel
- Payments and licensing: subscriptions and licence keys through an external payment provider
- AI: Claude and Gemini APIs, with API keys kept on a secure server, never inside the extension
You own the source code and the Chrome Web Store developer account.
Why Weras Labs
We are a small senior team led by our founder, Habip Dayan, and a software company that keeps its own extension live in the store. You talk directly to the developer building your extension and receive test builds you can load into your own browser at every stage. We are based in Turkey and work with clients worldwide in English.
What's included
Manifest V3 ready
Built for current Chrome rules, so it won't be pulled from the store.
In-page tools
Buttons, side panels and features that work with the content of the sites you visit.
Popup and options
A clean popup, an options page and keyboard shortcuts.
Accounts and sync
User sign-in and settings and data synced across devices.
Payments and licences
Free and paid plans, subscriptions, licence keys and trials.
AI integration
Summaries, writing and analysis with Claude or Gemini, keys kept server-side.
Store publishing
Listing, screenshots, privacy disclosures and review handled for you.
How we work
- 1
Idea and scope
We define which sites the extension runs on, who it is for and what it does.
- 2
Quote
A written proposal with permissions, screens, timeline and cost.
- 3
Build and test
Regular test builds you can load into your own browser.
- 4
Store launch
Chrome Web Store review, plus Edge and Firefox stores if needed.
- 5
Maintenance
Keeping up with Chrome updates and changes on target sites.
Frequently asked questions
How long does Chrome extension development take?
A focused extension that does one job usually takes 2–4 weeks. Commercial extensions with accounts, payments and a backend take 6–10 weeks. We allow a few extra days for store review.
How much does it cost to build a Chrome extension?
It depends on how many sites it works on, whether it needs a server, accounts and payments, and whether it uses AI. We prepare a free quote and can start with the core feature to keep the first release lean.
Will you publish the extension on the Chrome Web Store?
Yes. We prepare the listing, privacy disclosures and permission justifications and handle review. We take our own extension, HookSlayer, through the same process, so we avoid the common rejection reasons up front.
Can I sell a paid Chrome extension?
Yes, but the Chrome Web Store no longer handles payments. We set up subscriptions or one-off sales through an external payment provider and verify licences inside the extension.
Will it work on Edge, Brave and Firefox?
Chromium-based browsers such as Edge, Brave and Opera usually run Chrome extensions with minor changes. Firefox may need a separate package; planning for it early keeps the extra cost low.
Can you migrate our extension from Manifest V2 to V3?
Yes. We move background pages to a service worker, replace remotely loaded code and update network rules, then test the extension end to end before resubmitting it to the store.
Related services
- Web Application DevelopmentSaaS products, admin dashboards and custom web apps, built by one senior team from first release to production.
- AI IntegrationWe connect large language models like Claude, Gemini and GPT to your software, documents and workflows, safely and on budget.
- Business Process AutomationCustom automation that removes repetitive manual work: spreadsheet reports, data entry and syncing between the tools you already use.
- Claude AI IntegrationWe integrate Anthropic's Claude models into your product and workflows through the API, tool use and MCP servers.
Let's talk about your project
Describe what you need in a few sentences. We'll pin down the scope together and send a free quote within one business day. You talk directly to the developer.