Sebastian Käufer
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For Shopify, design and performance agencies

Your senior Shopify developer, under your brand.

Theme builds from Figma, complex Liquid and JavaScript, B2B logic, CRO implementation and tracking. Trained in Germany, ten years inside Munich agencies, now the extra senior pair of hands on your projects.

Get the partner kit Book a 20-min fit call
AVAILABILITY
Open now
PILOT TICKETS FROM
USD 450
OVERLAP
Full US day, EU afternoon
LANGUAGES
German (native), English, Spanish

Work that looks like yours

All case studies →
WITH AN AGENCYMigration alongside the client's marketing agency and ITZimply Natural → ARCHITECTURETwo brands from one Git codebase, 523/523 files sharedDual-brand lighting → MEASURED CROMobile add-to-cart 1.95% → 5.08%, reported honestlyNicebeam →

01 — HOW WHITE-LABEL WORKS

01
NDA by defaultYour client, your terms and our partnership stay confidential.
02
No client contactI join client calls only when you invite me, under your name.
03
No branding in codeIP transfers to you on payment.
04
Your toolsYour Slack, your ticket system, your Git repo, a staging theme per ticket.
05
QA before handoverTested on mobile and desktop, with a short walkthrough of what changed.
06
14-day bug warrantyAnything I shipped that breaks, I fix without a new quote.

02 — HOW A TICKET RUNS

  1. 01 · BRIEFYou send the ticket, Figma or Loom. I check the store first, then ask only what is still open.
  2. 02 · SCOPEWritten scope with what is in and out, and one fixed price.
  3. 03 · STAGINGBuilt on a duplicate theme or a branch. You preview before anything goes live.
  4. 04 · GO-LIVEPublished on your go, with the previous theme kept as rollback.
  5. 05 · HANDOVERA changelog your team can forward, written for your client.

03 — WAYS TO WORK TOGETHER

PILOT TICKETTest me on one real task.A small paid ticket from your backlog. You see scoping, communication and handover before anything bigger.FROM USD 450
FIXED-PRICE PROJECTOne scope, one price.Theme build, B2B setup, migration or CRO implementation. Written scope, milestones on staging.FROM USD 2,500
MONTHLY CAPACITYA reserved block, every month.A fixed monthly package for your ongoing tickets, with a weekly summary of what shipped.FROM USD 1,500 / MONTH

04 — BACKGROUND

I know agency work from the inside.

EARLY 2000s3-year dual apprenticeship, Fachinformatiker Anwendungsentwicklung, Munich
~10 YEARSFrontend in Munich agencies, incl. ADAC.de
~6 YEARSFull-time Shopify, 800+ completed projects
NOWSenior partner for brands and agencies worldwide, from Yucatán
First page of the partner kit
PARTNER KIT · PDF · EN / DE Two pages to forward to your team. Services, models, process and three short cases. Download the partner kit (PDF) DEUTSCHE VERSION →

05 — Questions agencies ask

Before you send the first ticket

Do you sign an NDA?

Yes, by default. Your client, your terms and our partnership stay confidential.

Will you talk to our client?

Only when you invite me, and then under your agency’s name. There is no branding of mine in the code, and IP transfers to you on payment.

How do you price agency work?

Fixed price per scope, agreed in writing before work starts. Pilot tickets start at USD 450, fixed-price projects at USD 2,500 and monthly capacity at USD 1,500.

Which time zone do you work in?

Yucatán, Mexico (UTC−6). That covers the full US working day and the afternoon in Europe.

Which tools do you work in?

Yours: your Slack, your ticket system and your Git repo, with a staging theme or branch per ticket.

What happens if something breaks after handover?

There is a 14-day bug warranty. Anything I shipped that breaks, I fix without a new quote.

Which Shopify work do you take on?

Theme builds from Figma, custom sections, B2B logic, CRO implementation, tracking and consent (GA4, Meta, Google Ads, Consent Mode v2) and migrations to Shopify. I do not build public Shopify apps.

Do you work with German-speaking agencies?

Yes. I am German, trained and worked for ten years in Munich, and work in German or English. There is a German version of this page.