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Custom Magento Extension Developer

Custom Magento extensions you’ll want to maintain

About 60+ open-source extensions on GitHub. Code that follows Magento standards (di.xml not class loader, plugins not rewrites, MFTF tests, proper docs). Hyvä-compat from day one.

  • PSR-12 + Magento Coding Standard, PHPStan level 6
  • MFTF + PHPUnit tests on every extension
  • Adobe Marketplace EQP-compliant builds
Free 60-min spec call Stores in 8+ countries shipped
  • 60+ Open-source extensions

    Free on GitHub at mage2sk & mage2kishan. Real-world battle-tested code, not portfolio fluff.

  • 100% Adobe Marketplace pass rate

    Every extension we submit passes Adobe’s code review on the first attempt. We know the rejection list.

  • Hyvä Compat shipped

    Native Hyvä compat module on every build — not a Luma-fallback hack.

  • MFTF + PHPUnit tests

    Functional + unit tests on every extension. Magento upgrades won’t silently break your custom code.

What you get

Six things every extension we ship has

Beyond the working feature — extensions are code your team or your customers will live with for years. Every build below ships with all six.

  • PSR-12 + Magento coding standards

    phpcs --standard=Magento2 + PHPStan level 6. Reviewed before commit, not after deploy. The next developer can read it.

  • MFTF + PHPUnit test coverage

    Functional tests for admin + frontend flows. Unit tests for business logic. Test data seeded via fixtures. Green CI before any merge.

  • Hyvä-compat from day one

    Native Hyvä module ships in every extension. No Luma-only blind spots. Your store renders correctly on both themes.

  • Adobe Marketplace ready

    Code passes Magento Coding Standard + Mage Extension Quality Program. Submission package + listing copy included if you want to publish.

  • Real documentation

    User guide (admin-facing) + dev guide (engineer-facing). Markdown in repo, screenshots, troubleshooting. We write docs the way we wish vendors did.

  • Future-proof for upgrades

    data:patch over installSchema, di.xml over class rewrites, plugins over preferences. Survives every Magento minor + major upgrade we’ve tested.

How it works

Five steps from idea to shipped extension

Daily commits to a private repo from week 2. You review on staging from day three of the build phase. No black box.

  1. 01

    Spec session

    Free 60-min spec call. We turn your “I want a thing that does X” into a written spec with admin UX, frontend behaviour, edge cases, and a test plan.

    Day 1
  2. 02

    Quote & reserve

    Fixed-price quote per spec. We commit to deliverables + test coverage + docs. You sign — we book the slot.

    Days 2–4
  3. 03

    Build & test

    Daily commits to private repo, MFTF/PHPUnit tests passing on every push, Hyvä-compat verified at every milestone. Review access from day three.

    Weeks 2–6
  4. 04

    Document & ship

    User guide + dev guide written. README, CHANGELOG, LICENSE finalised. Composer-ready package. Optional Marketplace submission.

    Week 6–7
  5. 05

    Maintain

    14 days bug-fix coverage. Future Magento-version compat updates available on 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 — we reply with a written quote within 24 business hours.

We will get back to you shortly.

What clients say

Vendors and store owners we’ve already shipped extensions for

Five-star average across Upwork, Clutch and direct LinkedIn referrals. Real clients, real shipped extensions.

Kishan was able to resolve an issue that many others could not solve.

Kishan was able to resolve an issue that many others could not solve. Great

MC

Mitch Chiba

10916234 Canada Inc.

Kishan is surely the best freelancer I worked with on upwork.

Kishan is surely the best freelancer I worked with on upwork. Always there to use his knowledge to help and sort any issue you may have in a pleasant and professionnal

NC

Nicolas Chevillot

Ecofone

This freelancer is the best i've used at Magento.

This freelancer is the best i've used at Magento. Absolutley brilliant at what they do. Would have no hesitation in recommending them

PS

Peter Stewart

CEO, No79 Design

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- I appreciate your expertise.

Kishan- I appreciate your expertise. Your work was timely and complete. When I have this task again, I will definitely hire you. Thank you so

JB

Juanita Berguson

Kingdom

Perfect job!

Perfect job!

GG

Gert Grunius

Trusted by stores in

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

Honest answers to the extension-development questions everyone asks

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.