Omnichannel POS Gateway Setup

I’m rolling out a new point-of-sale system that must handle both in-store swipes/taps and online checkout from the same payment backbone. The first milestone is to recommend the most cost-effective gateway or acquiring bank and explain why it suits my market, volumes, and risk profile— I don’t have a provider yet and need your guidance here.

Once the provider is agreed, I’ll need the full technical setup:
I Have Z90 Pos from Zons

• Hardware or software terminal configuration for countertop use (chip, magstripe, NFC).
• Secure API or SDK integration for my website so the same merchant account processes online sales.
• Card-tokenisation and PCI-DSS compliant handling of credit and debit cards— mobile wallets or QR payments aren’t required now, but the architecture should leave room for them later.
• Clear documentation outlining transaction flow, settlement timing, and how to reconcile in-store versus online batches.
• A short handover session showing me how to refund, run reports, and add future payment methods.

Please outline your experience with similar omnichannel setups, any preferred languages/platforms (JavaScript, PHP, Python, etc.), and how long you’ll need for each stage from provider selection to go-live.