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Custom Magento Extension Developer

Custom Magento extensions you’ll want to maintain

I build custom Magento extensions the same way I build my own 60+ open-source extensions on GitHub: di.xml instead of class rewrites, plugins instead of preferences, MFTF tests and proper docs, with Hyvä support from the first commit. It starts with a free 60-minute spec call, and you get a written spec before I quote.

  • PSR-12 + Magento Coding Standard, PHPStan level 6
  • MFTF + PHPUnit tests on every extension
  • Adobe Marketplace EQP-compliant builds
Free 60-min spec call Merchants in 25+ countries
  • 60+ Open-source extensions

    Free on GitHub at mage2sk and mage2kishan. They run on real stores, including mine, so you can read my code before you hire me.

  • 100% Adobe Marketplace pass rate

    Every extension I have submitted passed Adobe’s code review on the first attempt. I know what gets rejected.

  • Hyvä Compat shipped

    Every build gets a proper Hyvä compatibility module instead of a Luma fallback.

  • MFTF + PHPUnit tests

    Functional and unit tests on every extension, so a Magento upgrade can’t quietly break your custom code.

What you get

Six things every extension I ship has

A working feature is only part of it. An extension is code your team will live with for years, so every one I build includes all six.

  • PSR-12 + Magento coding standards

    phpcs --standard=Magento2 and PHPStan level 6, checked before every commit, so the next developer can read the code.

  • MFTF + PHPUnit test coverage

    Functional tests for admin and frontend flows, unit tests for business logic, test data from fixtures. CI has to pass before anything merges.

  • Hyvä-compat from day one

    Every extension ships with a Hyvä module, so it renders correctly on Hyvä and on Luma.

  • Adobe Marketplace ready

    The code passes the Magento Coding Standard and the Extension Quality Program. If you want to publish, I include the submission package and listing copy.

  • Real documentation

    A user guide for admins and a developer guide for engineers, in Markdown in the repo, with screenshots and troubleshooting notes.

  • Future-proof for upgrades

    Data patches instead of installSchema, di.xml instead of class rewrites, plugins instead of preferences. It has survived every Magento upgrade I have tested it on.

How it works

Five steps from idea to shipped extension

Daily commits to a private repo from week 2, and you can review on staging from day three of the build.

  1. 01

    Spec session

    A free 60-minute call. I turn “I want something that does X” into a written spec with the admin screens, frontend behaviour, edge cases and a test plan.

    Day 1
  2. 02

    Quote & reserve

    A fixed-price quote for that spec, covering the code, the tests and the docs. Once you sign, I book the slot.

    Days 2 to 4
  3. 03

    Build & test

    Daily commits to a private repo, MFTF and PHPUnit tests passing on every push, Hyvä checked at every milestone. You can review from day three.

    Weeks 2 to 6
  4. 04

    Document & ship

    I write the user and developer guides, finish the README, CHANGELOG and LICENSE, and hand over a Composer package. Marketplace submission is optional.

    Weeks 6 to 7
  5. 05

    Maintain

    I fix bugs for 14 days after delivery. Updates for new Magento versions are available on a retainer or per release.

    Days 30+
Pricing

Fixed prices. No per-hour surprises.

Pick the tier that matches your idea. Anything that’s out of scope after the spec gets quoted upfront before work starts, never billed silently.

  • Spec Audit

    $ 499 USD

    1-2 days · scope only

    Best for: Founders / PMs with a vague idea who need a written spec before quoting

    • 60-min spec call
    • User stories + acceptance criteria
    • Admin UX wireframes
    • Test plan + edge cases
    • Effort estimate (hours, not handwave)
    • Written spec doc you can take to any developer
    Get spec
  • Marketplace-Ready

    $ 9,999 USD

    6-10 weeks · scoped to your idea

    Best for: Vendors building extensions to sell on Adobe Marketplace or commercial license

    • Everything in Standard Extension, plus:
    • Adobe Marketplace submission package
    • Mage Extension Quality Program (EQP) compliance
    • Listing copy + screenshots + demo video
    • Licensing strategy (open-source vs commercial)
    • Customer-support runbook
    • 12-month post-launch upgrade compatibility
    Reserve Marketplace slot

Prices in USD. Quotes available in GBP / EUR / AUD / INR, ask in the booking form. Adobe Marketplace submission fees and any third-party API costs (e.g. ERP licences) are pass-through, never marked up.

Book your slot

Reserve your custom extension build slot

Booking takes 2 minutes, and I reply with a written quote within 24 business hours.

Message me on WhatsApp

No form to fill. Send me a quick message and I reply within 4 hours on IST working days, often sooner.

Helpful to mention

  • Company
  • Extension purpose
  • Extension type
  • Magento compatibility
  • Frontend compatibility
  • Spec state

These are already in the message for you. Just add your answers.

Message me on WhatsApp

Or save my number: +91 84012 70422

What clients say

Vendors and store owners I’ve built extensions for

Reviews from Upwork, Clutch and clients who found me on LinkedIn.

Kishan knows Magento very well.

“Kishan knows Magento very well. Our project is finished and I'll hire him again for next

HH

Hammad Hassan

After trying and failing with multiple development companies Kishan came to the rescue in our hour of need.

“After trying and failing with multiple development companies Kishan came to the rescue in our hour of need. Without hesitation Kishan jumped right in. He operated fast and with purpose. I was impressed with his diligent and methodical approach to tackle the issue. While...

ML

Michael Lin

Natonic

Kishan did an outstanding job building my Ayurvedic consultation website, complete with product integration.

“Kishan did an outstanding job building my Ayurvedic consultation website, complete with product integration. The entire process was seamless, and he was incredibly attentive to my specific business needs. His professionalism and expertise were evident, providing excellent...

SM

Simran Mahendraker

HH Formulations

Kishan was great to work with.

“Kishan was great to work with. I needed a small change to my site, with an attribute adding to appear on the frontend. Kishan completed this very quickly, and had the work completed the same day. I am very happy with the work completed by Kishan and would be happy to employ his...

CK

Chanette Kennedy

Kishan is a very competent and reliable Magento developer.

“Kishan is a very competent and reliable Magento developer. He was able to handle every task I gave him quickly and efficiently and his communication was top-notch. I look forward to continuing to work with

PJ

Philip Johnston

Newthink

Kishan is a great magento developer and he was a great asset to our organization.

“Kishan is a great magento developer and he was a great asset to our organization. He worked with us for a long time and he provided to us a lot of knowledge about magento. we are very gratefull with

AR

Alfredo Rodriguez

Cronapis

Trusted by stores in

  • United States
  • United Kingdom
  • Canada
  • Australia
  • Germany
  • France
  • Netherlands
  • India
FAQ

Extension development questions clients usually ask

When should I build a custom extension vs buy from Marketplace?

Buy when an existing Marketplace extension covers 80%+ of your need with reasonable config, it’s nearly always cheaper than custom and someone else maintains the upgrade path. Build custom when (a) no extension solves the problem, (b) you need it to integrate tightly with proprietary systems (ERP, PIM, custom checkout flows), (c) you’re selling the extension itself, or (d) the closest off-the-shelf extension would need so much customisation it’s cheaper to start clean. Our spec audit ($499) gives you the buy-vs-build call in writing before you commit.

How much does custom Magento extension development cost?

Three fixed-price tiers, no per-hour surprises:

  • Spec Audit: $499-1-2 days, just the spec, you can take it to any developer
  • Standard Extension: $2,999-3-6 weeks, single-purpose extension with Hyvä + Luma support, MFTF tests, docs, GitHub repo
  • Marketplace-Ready: $9,999-6-10 weeks, includes Adobe Marketplace submission package, EQP compliance, listing copy, screenshots, demo video, customer-support runbook

If your extension is unusually complex (multi-store ERP integration, custom payment gateway, headless GraphQL surface), we’ll quote per spec. No surprise invoices.

How long does it take to build a Magento extension?

Typical timelines:

  • Spec Audit: 1-2 days from kick-off call to delivered spec doc
  • Standard Extension: 3-6 weeks, week 1 spec sign-off, weeks 2-5 build + tests, week 6 docs + handover
  • Marketplace-Ready: 6-10 weeks, standard build plus Marketplace submission, EQP fixes, listing assets, demo video

Add 1-2 weeks if you want a UAT cycle with real users before sign-off.

Will my custom extension work with both Hyvä and Luma?

Yes, every extension we ship includes a Hyvä-compat module by default. We use the standard Hyvä compatibility module pattern (separate view/frontend directories under Hyva_*Compat) so the extension renders correctly on both Luma stores and Hyvä storefronts without code duplication. If you only need one frontend, we’ll happily skip the other and discount accordingly, tell us in the booking form.

Will it survive Magento version upgrades?

Yes, by design. We use data:patch over InstallSchema, di.xml over class rewrites, plugins / observers over preference, and declarative schema for any DB changes. None of those rely on internal Magento implementation details, they’re the documented extensibility surface. The Standard Extension tier includes 14 days of bug-fix coverage; Marketplace-Ready includes 12 months of upgrade compatibility (we test on each minor + patch release and ship a compat patch if anything breaks).

Can you submit my extension to Adobe Marketplace?

Yes, that’s the Marketplace-Ready tier ($9,999). It includes: full submission package (technical + marketing), Mage Extension Quality Program (EQP) compliance audit, listing copy, screenshots (admin + frontend), 60-90 second demo video, support runbook, and the actual submission to Adobe’s portal. 100% pass rate to date, every extension we’ve submitted has cleared Adobe’s code review on the first attempt because we run the EQP checks ourselves before submission.

Who owns the code I pay you to write?

You do, fully. When you pay us to build an extension, the source code is yours under a written assignment-of-IP clause in the contract. You can put it on your own GitHub, sell it, modify it, take it to another developer, open-source it, anything. We retain the right to reuse generic patterns (e.g. our boilerplate module skeleton, our PHPUnit test scaffolding) but never anything specific to your business logic, data, or branding.

Do you write tests?

Yes. Every extension ships with:

  • MFTF (Magento Functional Testing Framework) tests for admin + frontend user flows
  • PHPUnit unit tests for business logic, with fixtures for test data
  • phpcs --standard=Magento2 + PHPStan level 6 linting on every commit
  • GitHub Actions CI running the full suite on every push

We commit to green CI before any merge. The next developer picking up the extension can refactor with confidence because the tests catch regressions.

Will I get documentation?

Yes, two docs per extension:

  • User guide (admin-facing), how a store admin installs, configures, uses the extension. Screenshots, troubleshooting tips, common pitfalls.
  • Dev guide (engineer-facing), architecture, extension points, how to override, how to add custom logic on top, API reference.

Both are markdown in the repo (so version-controlled), plus a rendered HTML version. We write docs the way we wish vendors did when we’re consuming their extensions, thorough, honest, and answering the questions you’d actually ask.

What’s the difference between a plugin, observer, and rewrite, does it matter?

Yes, hugely. Quick rule of thumb:

  • Plugin, intercepts a public method (before/around/after). Magento’s preferred extensibility mechanism. Multiple plugins can stack cleanly. Use this first.
  • Observer, reacts to dispatched events. Use when Magento explicitly fires an event for what you need.
  • Preference (rewrite), replaces a class entirely. Last resort: only one preference per class wins, breaks other modules trying to do the same. We avoid this unless absolutely necessary.

Bad extensions abuse rewrites; good ones use plugins + observers. We default to plugins because they survive Magento upgrades.

Can I see your existing extensions before hiring?

Yes, 60+ open-source Magento 2 extensions on GitHub at github.com/mage2sk and github.com/mage2kishan. Real working code for SEO modules, B2B helpers, admin UX improvements, payment integrations, frontend widgets, and more. Browse the source, run the tests, read the docs, that’s the standard you can expect on your custom build. Several have been adopted by the Magento community and run on production stores.

What about post-launch support?

All tiers include 14 days of bug-fix coverage after handover, anything broken because of our build gets fixed at no extra charge. After that, two options: (1) per-incident support at our standard hourly rate (handy for one-off questions), or (2) maintenance retainer ($299, $999/month depending on extension complexity) covering Magento minor + major version compat updates, security patch verification, and minor feature requests. Marketplace-Ready tier includes 12 months of upgrade compatibility built-in.