• Online Stores · OpenCart

A cart that does not disappear: a person picks items on a phone, buys on a laptop, and it is the same order

A purchase rarely fits into one visit. A person fills a cart on the phone while commuting, opens the same store on a computer in the evening, and finds it empty. Or comes back two days later, once payday has arrived, and the cart is gone. Almost nobody will assemble the same set of ten items again: it is easier to go where it was saved. We make the cart survive a closed tab, a change of device and logging in to an account.

See how it works
Price
after a free audit
Guarantee
30 days after project sign-off
Focus
online stores, mostly OpenCart
Price
after a free audit
Guarantee
30
days after project sign-off
Focus
online stores, mostly OpenCart
Timeline
11
to 23 working days
Start
free cart review
Warranty
30
days from the date the acceptance act is signed
Response time
within 2 hours
Terms
under a written contract
What's included

Complete list of work and what you get as a result

  • a cart that survives closing the tab and coming back days later
  • carrying over what a guest added when they log in, without losing items
  • cart sync between phone and computer for logged-in shoppers
  • a cart lifetime agreed with you, set separately for guests and registered users
  • clear behavior when a product has become more expensive since it was added
  • clear behavior when a product is no longer in stock
  • clearing the cart on logout on a shared computer
  • analytics events to see how many shoppers return to a saved cart
When this service isn't right

What's not included — so there are no surprises at delivery

  • abandoned cart emails and any mailings
  • reserving stock for items in the cart, if you do not do this now
  • saving the cart in a way that bypasses cookie consent
  • moving carts from the old website during a migration
  • promises of conversion growth
Who it's for

Situations where this service delivers results

Scenario 1 of 4

A store where people buy from their phones

A mobile session is interrupted all the time: a call, the subway, a dead battery. If the cart does not survive the break, some orders never make it to payment for technical reasons.

We'll review your situation in a free audit
Free audit

A free cart review

We look at what exactly gets lost in your store and at which step: the causes vary, and half of them are fixed by a setting rather than a rewrite.

What we measure

  1. How long the cart lives nowIt often turns out that the session length is the default and measured in hours. This is the simplest case, and it is where to start.
  2. What happens on logging inA classic bug: the guest cart is silently replaced with an old saved one, and whatever was just added disappears. We check exactly this scenario.
  3. Whether registered users' carts are stored on the serverIf the cart lives only in the browser, syncing between devices is impossible in principle, and this determines the scope of work.
  4. How caching behavesOn sites with caching, the cart sometimes shows up as someone else's or empty. The cause is not the cart but the page being served from cache.
  5. What happens with prices and availabilityA cart saved for two weeks almost certainly contains an outdated price. You need a rule, not a silent change of the total.
  6. Whether cookie consent blocks savingIf the consent banner blocks saving, the cart will be lost precisely for those who did not click anything. This is visible straight away.

What you get

  • a list of scenarios in which your cart gets lost
  • an answer on what a setting fixes and what needs development work
  • an estimate of the work broken down by stage
  • an honest answer if there is no problem

Timeline: 2–3 working days

Why is it free

Half of all “the cart disappears” cases come down to session length or caching, and that is found in a couple of hours. We do not want to sell a rewrite where a setting is enough.

What's next

You receive a list of scenarios and an estimate. What to do next is your decision; the document stays with you.

Short form: your contact and site URL
Contract and paperwork

We work officially

Contract, act and invoice — for every project, not just large ones.

Trusted by6 brands

Trusted by: Kvant Energy, GYPSUN, Naturel Cosmetics, Pancer Protection, LUGI, BeeTech

Terms fixed in writing8 points

  • Contract, act and 30-day warranty

    Every project gets a written contract: scope, deadlines, amount, acceptance procedure. After delivery — act and invoice, then 30 calendar days of warranty.

  • Sole proprietor & bank transfer

    The contractor is a registered sole proprietor. Payment by invoice with closing documents.

  • Rights & access — yours

    Code, design and materials transfer to you after full payment. Domain, hosting, repository and analytics are registered to you.

  • Client portal instead of email chains

    During the project you get access to a portal: contracts, invoices, acts and project status in one place.

  • Sites in nine countries

    Our sites run in nine countries: besides Ukraine — Poland, Germany, Austria, England, Norway, Bulgaria, Moldova and Spain.

  • Verifiable numbers

    Every case in the portfolio comes with a link to a live site and a technical measurement.

  • Audit first, then pricing

    There is no price list on the site intentionally: the scope of the same work differs multiples between clients.

  • We say "no" when unsure

    If the task isn't ours or the deadline is unrealistic — we tell you upfront.

  • Contract, act and 30-day warranty

    Every project gets a written contract: scope, deadlines, amount, acceptance procedure. After delivery — act and invoice, then 30 calendar days of warranty.

  • Sole proprietor & bank transfer

    The contractor is a registered sole proprietor. Payment by invoice with closing documents.

  • Rights & access — yours

    Code, design and materials transfer to you after full payment. Domain, hosting, repository and analytics are registered to you.

  • Client portal instead of email chains

    During the project you get access to a portal: contracts, invoices, acts and project status in one place.

  • Sites in nine countries

    Our sites run in nine countries: besides Ukraine — Poland, Germany, Austria, England, Norway, Bulgaria, Moldova and Spain.

  • Verifiable numbers

    Every case in the portfolio comes with a link to a live site and a technical measurement.

  • Audit first, then pricing

    There is no price list on the site intentionally: the scope of the same work differs multiples between clients.

  • We say "no" when unsure

    If the task isn't ours or the deadline is unrealistic — we tell you upfront.

We sign NDAs on request. After completing the work, we delete our access to your services ourselves.

What affects the price

Why two seemingly identical tasks are priced differently

  • Sync between devicesSimply extending the cart's life in the browser is quick. A cart shared between phone and computer requires storing it on the server and resolving conflicts between two versions.
  • Merging on loginYou need to decide what the system does when a guest with a filled cart logs in to an account that already holds a different one. Add, replace or ask: each option has its own cost and its own consequences.
  • LifetimeAn hour and a month are different storage requirements. A long lifetime means more outdated data and more rules about prices and availability.
  • Price rulesSilently recalculating the total is the cheapest option, but it is the same surprise at the last step. An honest warning about a price change costs more and does not burn trust.
  • CachingIf pages are served from cache, the cart needs separate handling. This is a common cause of a “someone else's” cart, and it affects more than just the cart.
  • State of the cart codeThe platform's standard cart is easy to change. If it has already been rewritten on top, we first need to understand the existing logic, and that can be the larger part of the work.
Cases

Tasks and results in numbers — all metrics measured by us

an online store delivering sweets, snacks and gift sets

Task
Sell sweets, snacks and gift sets with delivery across Ukraine: a catalog with filters by type and occasion, a cart with a choice of delivery, online payment. A particular focus is the speed of the mobile version, because in this niche most orders are impulse purchases made from a phone.
Solution
A store on OpenCart 3.x (octemplates/OCT theme, HTTP/2). 5 online payment methods are connected — LiqPay, WayForPay, Privat24, Visa, Mastercard — and 4 delivery methods: Nova Poshta, Ukrposhta, pickup, courier. Free delivery to a Nova Poshta branch on orders from 2,500 UAH is set up (a banner on the home page), and customers can get in touch via Telegram, Viber, WhatsApp, Instagram, Facebook.
Result
As of 31 July 2026 the store is up (HTTP 200, HTTPS): first server response 403 ms, full HTML load 532 ms; LiqPay, WayForPay and Privat24 online payment and Visa/Mastercard cards are connected, plus 4 delivery methods; the home page shows free Nova Poshta delivery on orders from 2,500 UAH.

2PM

an online retail underwear store with a catalog of more than 110,000 product items

Task
Sell underwear online across Ukraine so that shoppers can pick their size themselves without consulting a manager, which reduces returns. Every size and color is added as a separate item, so the catalog grows to a hundred thousand pages: the task is to hold such a structure within a single store, keep navigation by category and brand, and leave the pages fit for indexing.
Solution
A store on OpenCart 3 (oct_luxury theme by Octemplates, Apache, HTTP/2, gzip). Three language versions: ru at the root, /ua/ and /pl/. The sitemap is built as an index of 42 sub-sitemaps (39 product ones of 3,000 URLs each + categories, brands, info pages), which is the correct way to serve a catalog of this size. The product page carries full product JSON-LD markup: Product, Offer, Brand, MerchantReturnPolicy, OfferShippingDetails, ShippingDeliveryTime, DefinedRegion, ImageObject. The home page has ClothingStore store markup, WebSite/SearchAction, ContactPoint, PostalAddress, OpeningHoursSpecification, GeoCoordinates. Delivery by Nova Poshta in three options (branch, courier, parcel locker) plus Ukrposhta. Analytics and advertising: GTM, GA4, Google Ads, a remarketing module passing product_id to Google Ads and Facebook.
Result
115,456 product items — the figure confirmed by two independent methods: standard OpenCart search gives 1,154 pages of 100 items plus 56 on the last one (115,456), and the sitemap gives 112,646 unique product URLs, a 2.4% discrepancy. This is the largest catalog in the measured sample. A product page returns the first response in 0.39 s, a category page in 0.47 s. 129 categories, 334 brands, three language versions. Measured 1 August 2026.

Did not find your case?

Describe how it works on your side — we will tell you whether “Persistent shopping cart across sessions and devices” fits and what it means in your situation. No brief and no call: one question, one answer.

Process steps

Transparent stages with approval at every step

Total duration:5–20 days

  1. Reproducing the losses

    2–3 working days

    We go through the scenarios in which the cart gets lost: a closed tab, another device, logging in, returning a day later. We record what exactly breaks and where.

  2. Agreeing on the rules

    1–2 working days

    We agree on the cart lifetime, the merging behavior, and how to react to a changed price or an item that has disappeared. These decisions are yours; we show the consequences of each.

  3. Storage

    3–7 working days

    We implement cart saving so that it survives the session and, for logged-in users, lives on the server and is shared across devices. We work in a test environment.

  4. Merging and refreshing

    2–5 working days

    We build correct merging of the guest cart with the saved one, price and availability checks on restore, and clear messages about changes.

  5. Edge cases

    2–4 working days

    A shared computer and logging out, two tabs at once, caching, an item that disappeared between visits, cookie consent not given. This is where leftover bugs usually hide.

  6. Launch and monitoring

    1–2 working days

    We roll out the changes, set up analytics events for cart restoration, and watch for a week to see whether the complaints have stopped. After that, the 30-day warranty applies from the date the acceptance act is signed.

Technologies & integrations

What we build on and what it connects to

Stack

  • OpenCart
  • WooCommerce
  • PHP
  • JavaScript
  • TypeScript
  • MySQL
  • MariaDB
  • Redis
  • Next.js
  • Git

Integrations

  • Google Analytics 4
  • Google Tag Manager
  • CRM
  • Email
  • Telegram
A persistent cart or a standard session

How this option differs from the alternative

The cart lives as long as the browser sessionOur approach
Coming back a day laterempty, start againthe cart is still there
Switching to another deviceimpossible in principleworks for logged-in users
Logging in to an accountoften silently overwrittennew items are added to the saved cart
Outdated pricesno problem, because the cart does not last that longneeds a separate rule and a warning
When the standard session is enoughfine for cheap goods with a quick decisionoverkill for an impulse purchase in a single visit
What we need from you

We can't start without this — best to prepare in advance

  1. how long the cart should live after the last visit
  2. whether the store has accounts and how much they are actually used
  3. what to do when the price has changed since the item was added
  4. what to do when a product is out of stock
  5. whether you reserve products added to the cart
  6. who on your side accepts the work
If something is missing — let us know, we'll help you gather it or do it as a separate task.
FAQ

Most frequently asked questions — with concrete answers

How long should a cart live?

It depends on the product. For food and small items a week is already too much; for furniture or electronics a month is normal, because the decision takes a long time to mature. We ask how long your customers typically take to decide on a purchase and add a margin. The main thing is not to leave the default hour or two: that is the length of a session, not of a decision.

What if the price changed while the cart was waiting?

Anything but a silent recalculation. The right way is to show the new price and say plainly that it has changed since the item was added. Some people will back out, and that is normal: the worse outcome is when a person notices the discrepancy at the payment step and stops trusting all your prices.

The cart gets lost when logging in to an account. Is that the same task?

Yes, and it is the most common specific case. A person fills the cart as a guest, decides to log in before checkout, and the system replaces the cart they just filled with an old saved one. The correct behavior is to merge, not replace, and to say what has been added.

Will the cart be shared between phone and computer?

For those logged in to an account, yes, because then the cart is stored on the server and tied to the person. For a guest it is technically impossible: browsers know nothing about each other. This is not a limitation of the implementation but how the web works.

Won't there be problems on a shared computer?

That is exactly why we separately handle clearing the cart on logout. A cart that shows someone else's purchases on a shared work or home computer is not just an inconvenience but an unpleasant situation for the shopper. We always test this scenario.

Do you do abandoned cart emails?

No, that is a different task, and we do not mix it in here. Here we are responsible only for making sure the cart does not disappear by itself. Mailings are separate work with their own requirements for consent to communication, and there is no point starting them before the cart stops getting lost.

How long does it take?

11 to 23 working days. Extending the cart's life within the browser takes a few days. A cart shared between devices with correct merging and price checks is closer to the upper limit. If the cart has already been rewritten, we first have to make sense of the existing logic.

Will this increase sales?

We do not name a figure. What certainly goes away are losses for technical reasons: a person wanted to buy, came back and did not find their cart. We set up analytics events on cart restoration so you can see how many shoppers actually come back to it and judge for yourself.

Demo

Your catalogue on a phone screen

This is how your store can look on a phone: a collection banner, popular products and a cart one tap away. Tap “Add to cart” and the counter in the header updates, just like in a real store.

  • Collection bannerThe first screen shows what is new, not a logo.
  • Product cardsPhoto, price and a button — no extra page to open.
  • One-tap cartThe counter in the header updates instantly, like in a real store.
Stores in the portfolio
This is a demo interface, not a client's store. Live projects are in the portfolio.
SHOP
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  • Street Sneakers2 390 ₴
  • Active Shorts890 ₴

Let's see where exactly your cart gets lost

We will go through the loss scenarios and tell you what a setting fixes and what needs development work. The review is free, and we reply within 2 hours.

From measured cases115,456 product items

View cases
  • Reply within 2 hours
  • No commitment
  • We work under a contract

There is no price list on the site on purpose: the same work differs several times over between two clients, and a “from” figure explains nothing in that case. First a free audit — we count your pages, duplicates and speed — then we name the sum and the deadline and fix both in the contract.