Custom Software & SaaS Development

Browser Extension Engineering

Custom intelligence overlays and browser utilities that interact securely with third-party web platforms.

Timeline
6–12 weeks
Engagement
Senior, embedded
Pricing
Outcome-based
Discipline
Custom Software & SaaS Development

⏚ Summary

What this engagement is, plainly.

Browser extensions are the highest-leverage product surface most teams ignore. We build them with the security, performance, and store-policy discipline that keeps them shippable and unblockable.

Problems we solve

  • You want to overlay intelligence on a SaaS your team uses, but the vendor doesn't ship an API.

  • Your existing extension is fragile, fails store review, or breaks every Chrome version.

  • You need to interact with sensitive third-party data without compromising user trust.

⏚ Approach

How we run this engagement.

  1. 01Phase

    Manifest V3 as the baseline

    Service workers, declarative content scripts, strict CSP. We design for the current and next browser policy regimes, not the one being deprecated.

  2. 02Phase

    Third-party DOM as contract

    We treat the target page as an unstable API. Selector strategies, fallback flows, and contract tests that flag breakage before users see it.

  3. 03Phase

    Security first

    Permissions minimized, data flows audited, code signed. Store review is a side-effect of how we build.

⏚ Deliverables

What you get, signed off.

  • Manifest V3 extension across Chrome / Firefox / Edge

  • Selector strategy + breakage detection

  • Settings + auth flow

  • Update + version-pinning system

  • Store submission + review playbook

⏚ Stack we typically use

Tools, not religion.

We pick on workload and team shape, not on fashion. Anything below is a default — swappable when your context demands.

  • TypeScript
  • React
  • Manifest V3
  • Plasmo
  • WXT
  • Playwright

Outcome

An extension that passes store review on first submit, survives quarterly browser updates, and doesn't break when the target site redesigns.

⏚ Frequently Asked

About this service, specifically.

⏚ Engagement Initiation

Have a hard problem worth doing once, well?

We take a small number of engagements per quarter. If your program needs serious operators, we'd like to hear about it.

Start a Projecthello@xpansionit.com

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