For Shopify sellers who also sell on Amazon

Two fulfillment lanes. One is cheaper on every order.

WhatBox reads each Shopify order and prices it against Amazon MCF and your in-house shipping — Prime fee included — then routes it to the lane that wins. Amazon's own app can't do that: it profits when you pick Amazon.

Live and running in production today — not yet listed on the Shopify App Store. Apply for free beta access, or join the waitlist to hear about public launch instead.

Order #10482 · Decision card
Amazon MCF
arrives Jul 23
$9.24
In-house
box + postage + labor
$6.44
The category gap

Amazon just built this exact feature. It still can't be neutral.

Amazon now ships its own MCF + Buy with Prime app for Shopify. It's good at exactly one thing: making sure every eligible order routes onto Amazon. That's not a bug — Amazon earns the MCF fee (and the Prime fee) either way, so its own app was never going to tell you when shipping in-house is actually cheaper. Same story with every other MCF app we've evaluated: connect Amazon, sync stock, route orders — never a dollar amount, never a real comparison.

WhatBox computes your actual in-house cost — box, postage, labor — and puts it next to Amazon's real fee, Prime fee included, on every order, before anything ships. It works for every merchant out of the box: WhatBox has built-in carrier rates (USPS/UPS/FedEx/DHL), so you don't need your own shipping account to get a real number.

The decision engine

Every order. Both real costs. The cheaper way, automatically.

This is the whole product, distilled into one card on every order.

  • A 3D bin-packing engine packs every incoming order against your real box inventory — it knows your boxes and pulls item dimensions and weights straight from your Amazon listings. Soft goods that fold down get their own separate packing size.
  • Simultaneously quoted against Amazon MCF in real time: the actual fee and the promised delivery date, across speed tiers (Standard / Expedited / Priority).
  • Your in-house cost, with real carrier rates — WhatBox's own built-in USPS/UPS/FedEx/DHL rates (no shipping account required), or your own ShipStation negotiated pricing if you have one — plus box cost and labor. The real number shows the moment you open the order.
  • The result lands right on the Shopify order page: Amazon MCF $9.24 · arrives Jul 23 vs In-house $6.44 — In-house cheaper by $2.80, with a plain-English "why" — cost, delivery speed, inventory age, keeping the order together, your effort — each shown as a labeled chip.
  • One screen lists every order awaiting a fulfillment call, with the MCF-vs-in-house comparison right on the row.
  • Filter to simple one-item orders, or the ones where MCF wins, then send in bulk or one at a time — or self-fulfill in a click.
  • Split orders: send FBA-stocked lines to Amazon, ship the rest yourself. WhatBox does the honest three-way math for a split shipment — two packages, two costs, one true total.
The Decide command center

Every order needing a call, on one screen.

Work through a whole day's orders without opening each one individually.

One-click fulfillment + Autopilot

Commit with the number already on screen — or let it run itself.

No guessing what Amazon will charge after the fact — you see it before you click.

  • Send to Amazon MCF with the exact fee shown before you commit, or confirm ship in-house — every order ends in a clean, logged decision.
  • Autopilot routes orders for you when you're ready: weighted by price, delivery speed, inventory age, and order completeness, with hard guardrails you set (days-of-cover, stock buffer). Run it in Suggest mode first — it recommends, you click — then flip to Auto.
  • Blank-box and non-Amazon-carrier options for channels that require them (e.g. Walmart) — per account, per channel, or per order.
  • Custom packing-slip message, per store and per order.
  • An optional gate holds every MCF-eligible order in ShipStation until you decide — so anything sitting in Awaiting Shipment is cleared to ship and can never double-ship against an MCF send.
  • ShipStation copies of MCF-sent orders are automatically put on hold, so nobody double-ships from the other direction either.
Never double-ship

The ShipStation gate.

One order, one shipment — guaranteed, not just hoped for.

The watchdog Nobody else has this

Amazon's promise, checked automatically.

You find out when something's wrong before your customer has to tell you.

  • Every order sent to Amazon is tracked against Amazon's own promised delivery date.
  • Stuck too long, past the promise, undeliverable, returned, or lost? You get an email with the reason — and one-click fixes: retry at Amazon, or release it back to in-house shipping.
  • Delivery is followed all the way to the customer's door — confirmed delivered, or flagged. Optional delivery-confirmation emails to you.
  • Edit an order after sending? WhatBox flags it so you can cancel and resubmit the corrected order before Amazon ships.
  • Account-wide Amazon delivery-speed stats — your real Standard vs. Expedited door-to-door times and on-time rate.
  • Aged-stock nudge: when shipping in-house is cheaper but you have FBA stock aging toward long-term-storage fees, WhatBox says so — sending via MCF draws it down.
  • Restock advisor: orders you couldn't fulfill via MCF for lack of FBA stock, with the missed savings quantified. FBA + AWD (Amazon Warehousing) aware.
Inventory intelligence

Your stock levels, factored into every decision.

The cheaper option isn't always available — WhatBox tells you when that's costing you.

The money layer

See the P&L, not just the tracking number.

Every dollar, on every order, written down in plain English.

  • Savings counter: "Saved with WhatBox: $X" — counted only when an order actually shipped the cheaper way. Honest math, stated right on the card.
  • Per-order fulfillment P&L: shipping collected minus postage, box, and labor — shown in your store's currency. Green or red, order by order.
  • Prime-fee advisor: flags which SKUs are actually worth turning Buy with Prime on for, based on real order economics — so you're not blanket-enabling a 3% fee on units where it never pays for itself.
  • Price guard: an alert when your Shopify price undercuts your Amazon price. One-click fixes — and it's raise-only, WhatBox never lowers your prices for you.
  • Storefront delivery-date badge for product pages ("Order within 2h — get it by Tuesday").
  • Full order history with reasons, in plain English; order tags for Shopify Flow automation.
Coming soon

What's next

These aren't live yet — they're on the roadmap.

International marketplaces & carriersSoon

The same math, beyond the US — today's comparison is US-first.

Live checkout ratesSoon

Real shipping rates at checkout, not estimates.

Multi-marketplace per connectionSoon

One connection covering more than a single Amazon marketplace.

More fulfillment networksSoon

As they open up (e.g. TikTok's new FBT), the decision card generalizes — Amazon vs. TikTok FBT vs. in-house, cheapest wins.

Category contrast

One price. Every marketplace. Real rates included.

No add-on menu, no shipping account required.

Other MCF apps — Amazon's included

  • Amazon's own MCF + Buy with Prime app: puts every eligible order on Amazon. That's the business model, not a neutral read — Amazon earns the fee either way.
  • Per-country pricing that stacks: per-marketplace fees, then extra for inventory sync, bundles, imported orders, a blank box, blocking AMZL. A realistic single-country U.S. setup lands around $60–120+/month.
  • Configuration stays locked until you approve payment.
  • No dashboard. No cost visibility anywhere.
  • When something fails, the fix is: recreate the order in Seller Central yourself.

WhatBox MCF

  • No stake in which lane wins — prices both, Prime fee included, and routes to whichever's actually cheaper, order by order.
  • One flat price. Every marketplace, sync included — never gated behind an add-on.
  • Real carrier rates built in — no shipping account required to get an honest in-house number.
  • See your savings before you pay a cent.
  • The watchdog catches problems automatically and hands you one-click fixes — not "go redo it in Seller Central."
Simple pricing — launch pricing

Start free. One flat price, every marketplace.

Free to install, not to run — WhatBox pays for itself on the orders it keeps off Amazon MCF. Launch pricing, subject to change as we head to public launch. Metered on orders actually shipped through Amazon MCF, never per marketplace.

Free

$0 / month
  • Up to 10 MCF-shipped orders/mo
  • All features, every marketplace
  • No card required
  • Decision card on every order
Join the waitlist

Growth

$79.99 / month
  • Up to ~750 MCF-shipped orders/mo
  • Everything in Standard
  • 14-day trial
Join the waitlist

Scale

$99.99 / month
  • Up to ~2,000 MCF-shipped orders/mo
  • Everything in Growth
  • 14-day trial
Join the waitlist

Every plan includes every marketplace and all features — no add-on menu, ever. Metered only on orders actually shipped through Amazon MCF ("pay when we ship through Amazon"). 14-day trial on paid plans. No card required for Free. Order-volume caps are provisional launch pricing.

Beta program

Want in before public launch? Become a beta tester.

We're opening up free access to a small group of merchants ahead of the public Shopify App Store launch. You'll run WhatBox MCF on real orders at no cost — in exchange, we'll lean on you for feedback: bugs, rough edges, and the stuff that's confusing before it's obvious to us.

This is pre-launch software. Expect some sharp edges, and use it with the caution that implies. If that's a fair trade for free access and a direct line to shape the product, we'd like to hear from you.

Apply for beta access

Also importing inventory by the container?

WhatBox ERP knows what every unit really costs — purchasing, receiving, and true landed cost in one place. Built by the same team.

Meet WhatBox ERP →
WhatBox Built by a merchant,
not a vendor.
Founder story

WhatBox MCF came out of Princeton Popcorn.

Princeton Popcorn is a real popcorn business selling on both Shopify and Amazon. Its founder ran both channels and kept guessing which orders MCF should ship — no tool would just show the two costs side by side. So he built one.

WhatBox MCF has been running in production on Princeton Popcorn's own orders since day one. It's not a concept — it's the tool that stopped the guessing, now being opened up to other merchants who carry FBA inventory and pack their own DTC orders.

WhatBox is built and operated by Snorka, LLC — a US software company run by an active Shopify + Amazon seller.

FAQ

Questions merchants ask us

It's live and running in production — just not yet listed on the Shopify App Store (we're in a custom-distribution phase ahead of public launch). Join the waitlist and we'll bring you in for early access.

Free up to 10 Amazon-fulfilled orders/month, then $49.99, $79.99, or $99.99/month depending on volume — every plan gets every marketplace and every feature, metered only on orders actually shipped through Amazon MCF. Paid plans include a 14-day trial.

Amazon's app is great at exactly what it's built for: putting your orders on Amazon. It doesn't — and structurally can't — tell you when shipping in-house is actually cheaper, because Amazon earns the fee either way. WhatBox is the neutral layer underneath: it prices every order against both lanes, Amazon MCF with the Prime fee included and your real in-house cost, and routes to whichever wins, even when that's not Amazon. It also flags which SKUs are actually worth turning Buy with Prime on for, so you're not eating a 3% fee on units where it never pays off.

No — Buy with Prime and the Prime badge are Amazon's own program. WhatBox is the decision layer that tells you when using it (or MCF) is actually worth it, order by order and SKU by SKU. Think of us as the referee, not the badge.

No. WhatBox MCF has built-in carrier rates (USPS/UPS/FedEx/DHL), so you get a real in-house cost with zero setup. If you already have negotiated rates in ShipStation, WhatBox will use those instead for an even more precise number.

Yes. Split orders send some lines to Amazon MCF and the rest through your own process, with honest three-way math since a split ships as two separate packages.

No. Price guard is raise-only — it alerts you when your Shopify price undercuts Amazon and gives you one-click fixes, but it never lowers your prices automatically.

The watchdog tracks every sent order against Amazon's own promised date. If it's late, undeliverable, returned, or lost, you get an email with the reason and one-click fixes — retry at Amazon, or release it back to in-house shipping.

Beta means using WhatBox MCF now, free, on your real orders — in exchange for feedback while things are still being smoothed out. The waitlist is lower-commitment: it just gets you an email when WhatBox MCF is publicly available on the Shopify App Store. Pick whichever fits how hands-on you want to be right now.

When you route an order through Amazon MCF, we use your buyer's name, address, and phone number solely to create that buyer's own MCF shipment via Amazon's SP-API — never for marketing, resale, or analytics. Full details, including what we collect, how it's stored, protected, shared, and deleted, are in our Privacy Policy.

Contact

Questions, support, or a demo — we answer.

Live chat

Click the chat bubble in the bottom-right corner of any page.

Book a call

30-minute meeting →

Join the waitlist

Not ready for beta? Hear about public launch instead.

The waitlist is the lower-commitment option — no beta, no rough edges, just an email when WhatBox MCF is publicly available on the Shopify App Store. Want to use it now instead? Apply for beta access.