One integrationTo customers in 30+ countriesFor free.
Support

Get in touch

Questions about cross-border selling, integrations, or logistics? Reach us by phone, email, or the form below — our team typically responds within hours.

Response
< 24h
Languages
EN & LT
Support
Free
Call us directly+370 664 80225Email support[email protected]
EET (Kaunas, Lithuania)Mon — Fri, 9:00 — 18:00
Email us
Send a message

Write to us directly

Fill in the form below and we will get back to you as soon as possible.

This opens your email app with your message ready to send.

Countries served
30+
Commissions
Zero
Setup time
Guided
Product sync
Real-time
Our offices

Reach us directly

Whether you need technical help, want to discuss a partnership, or just have a question — we are here for you.

Headquarters

Europos pr. 34-47
Kaunas, Lithuania
UAB "Mastersel" 307424990

Located in the heart of Europe for optimal cross-border logistics routing.

How it works

Email Support

For API integration inquiries, logistics tracking, and general support.

[email protected]

We typically respond within a few hours during business days.

Phone

Prefer to talk? Call us directly for immediate assistance with your account or integration.

+370 664 80225

Available Monday — Friday, 9:00 — 18:00 EET.

Support topics

How can we help?

Browse common support areas or contact us with your specific question.

FAQ

Frequently asked questions

How do I integrate my e-commerce store?

Create your account, review the partnership agreement and connect your store. Setup and publication times depend on your platform, product information and marketplace review.

Who handles international returns?

Mastersel handles the entire reverse logistics process. If a customer in another country returns an item, we process the local return, consolidate shipments, and route the inventory back to your warehouse efficiently.

Is the service truly free with zero commissions?

You keep 100% of your listed base price. Mastersel earns revenue by adding our own competitive markup to the final retail price, which we also use to cover all shipping and localization costs.

How are customs and VAT handled?

Our automated logistics engine pre-clears customs and manages VAT compliance for cross-border shipments, ensuring your packages never get delayed at international borders and buyers never face unexpected fees. You don’t need to handle international tax payments, as Mastersel acts as the sole purchaser, reflected in your sales invoices.

What is the typical response time?

We aim to respond to all inquiries within 24 hours on business days. Most requests are answered within a few hours during European business hours.

How does onboarding work?

Installation is completely self-service. Install the Mastersel plugin for your platform, and your products will sync automatically. No calls or meetings required. Start selling now.

Can I migrate from another platform?

Yes. If you are switching from another platform, our plugins ensure a smooth transition. Your product catalog is imported and synced from your existing e-commerce store — no manual data entry required.

Which languages do you support?

Our support team communicates in English and Lithuanian. Product listings are automatically localized into the relevant languages for each target market.

Why responsive support matters

Running a cross-border e-commerce operation means dealing with multiple currencies, languages, tax regimes, and logistics networks simultaneously. When something goes wrong — a customs delay, an inventory mismatch, a courier routing issue — you need answers fast.

Support that understands e-commerce

Our team knows the difference between an HS code and a VAT IOSS number. Whether you are troubleshooting your store integration, checking on inventory sync status, or resolving a customs clearance question, you will get a technically informed answer — not a scripted response.

From setup to scale

We support sellers at every stage: first-time cross-border sellers connecting their store, growing businesses optimizing courier routing, and established brands expanding their logistics network across new European markets. Your success is our success.

Ready to expand globally?

Connect your store for free and start selling across 30+ countries today.