Integrations · Fondy API

Fondy integration: payments and subscriptions on the site

Fondy integration is the connection of the payment gateway so that the buyer pays by card directly at the checkout, and the order changes to the paid status. We take care of it when one card acceptance is not enough: payment in several currencies, regular subscription debits or settlement from a buyer from abroad is required. These three scenarios differ in the amount of work by a factor of five, so we start with a free checkout check, and not with installing the module. The term is 7–14 working days.

See how it works

Price: after a free audit
Guarantee: 30 days after project sign-off
Term of works: 7–14 working days, the upper limit is subscriptions

Price: after a free audit
Guarantee: 30; days after project sign-off
Term of works: 7–14; working days, the upper limit is subscriptions
Screening of the script before the estimate: 1-2; working days, free of charge
The widest checkout in our measurements: 10; payment methods, tool shop, 07/31/2026
The largest catalog where we counted payment: 54,302; products, 5 methods of calculation
What is most often missed in self-made modules: gateway response signature verification
Guarantee: 30; calendar days for completed work

Free audit

Free check before connecting the gateway

Before connecting another payment provider, it is worth answering a simple question: what does it do that the existing ones do not. The check gives an answer in one or two days.

What we measure

What script do you need?One-time payment, regular debits or payment in several currencies. These are three tasks of different labor intensity, and it is wrong to confuse them in the estimate.
What is already connectedWe go through the checkout as a buyer and record the real list of payment methods. Sometimes after that it turns out that a new gateway is not needed.
Currencies and foreign buyersIf you sell outside the country, we check in which currency the invoice is issued and what the buyer sees on the payment page.
Statuses and callbacksHow does the status of the order change now after payment and whether the signature of the gateway response is checked.
Security of the payment step itselfWe look at the certificate and redirects from the root of the domain. In the tool's measured store, the certificate was valid, and the bare domain led to insecure HTTP — and the browser said "Not secure" exactly where the card was entered.
Subscriptions, if neededRegular write-offs require separate logic: continuation, cancellation, failed write-off, and notification to the buyer. This is the largest part of the work, and it is better to estimate it before the start.

What you get

Checkout report: what's available now and what's missing for your scenario.
Description of the payment scenario that we will implement, in simple words.
Evaluation of works and term.
A 20-30 minute conversation with you and your accountant.

Timeline: 1-2 working days

Why is it free

Because in half of the cases, after analysis, it becomes clear that the task is solved by the existing gateway. This is a normal answer and we give it for free.

What's next

After the inspection, we give an estimate and a deadline. If an additional provider is not needed, we will say so.

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

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

What script are you enablingA one-time payment in hryvnia is connection and testing. Multi-currency adds functionality with amount display and conversion notes. Subscriptions add separate state logic. The difference between the first and third option is times, not percentages.
How many subscription states need to be processedContinuation, buyer cancellation, failed charge, change card, retry after N days, notifications every step of the way. Each state is a code, a letter, and a separate test run. This is where the upper term limit lives.
Checkout status at the startIn a store with a normal payment step, the gateway is placed in a row. If the statuses are set on the "thank you" page, this logic must first be transferred to the server - otherwise, the new provider will simply add a second channel of the same hangs.
Platform and versionOpenCart and WooCommerce often have a ready-made module, and the work is reduced to setting it up, reading its code and testing it. A self-written checkout or a showcase on Next.js means that we write API calls under your code - the volume is larger, but no other code is added to the project.
Return and reconciliationIf the return is issued manually by the manager in the provider's office, we do not make a block in the admin at all. Partial returns directly from the order are access rights, API rejection processing and a separate report for the accountant with the currency of each receipt.

Who it's for

Situations where this service delivers results

Scenario 1 of 5

Your customers pay from abroad

It is not the language of the interface that decides, but the currency of the account and whether the card of a foreign bank is accepted. In the furniture store we measured for the Spanish market, there are exactly two ways of payment — online card and transfer. For one country, this is enough, for several markets, the issue of currency comes out of the first order.

We'll review your situation in a free audit

What's included

Complete list of work and what you get as a result

Payment by card at the checkout — Visa, Mastercard, Apple Pay, Google Pay: the buyer pays from the phone in two taps
Account in the currency of the scenario: the person sees the amount that will be debited by the bank, not an approximate conversion
Regular write-offs with continuation, cancellation and failed attempt handling — the subscription lives without manual control
Callback handler with signature verification: the "paid" status is set by the gateway, not by anyone who knows the address
Server-side status re-request - the order is closed even when the buyer has closed the tab
Successful and unsuccessful checkout pages with the cart saved: after the bank declines, the person pays a second time, instead of collecting the cart again
Full or partial refunds from the administration - the manager does not write to the provider's support for every case
GA4 purchase event with amount and currency: Reports show money, not just the number of orders
Test mode and keys in environment variables - the secret does not get into the repository and does not go with the theme backup
Acceptance on live payment with a minimum amount and return, then a guarantee of 30 calendar days

When this service isn't right

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

The contract with the provider and the verification process are drawn up by you
Commissions, tariffs and currency terms
Accounting of currency receipts
Legal texts: offer, return conditions, subscription rules
Fiscalization of payments is a separate task

Process steps

Transparent stages with approval at every step

Total duration:4–14 days

Script verification and access
1-2 working days
We go through your checkout as a buyer, record the available payment methods and the place where the order status changes. In parallel, we accept the seller's ID and secret key from your account. The output is a script described in words, according to which the rest is calculated.
Gateway and callback
1-3 working days
We enable card payment in the checkout and write the gateway response handler: signature verification, identity by order number, repeated status request from the server. Here are the pages of successful and unsuccessful payment with the saving of the shopping cart.
Currencies and amount display
1-2 working days
We decide what the buyer sees: the price in the currency of the account or conversion at the exchange rate. We print the amount in the currency in which the invoice is issued and add a note - otherwise, after debiting, the question will fly in, why the bank has a different number.
Subscriptions with all states
3-6 working days
The stage is turned on only when necessary. Continuation, one-click cancellation, failed debit with retry, card change, letters to the buyer and individual statuses in orders. Together with the accountant, we agree on how these events look in the reconciliation.
Live payment, return, transfer
1 working day
We pay the minimum amount with our own card, check the status of the order and immediately issue a full or partial refund. Next, access, a brief instruction for the manager, and the warranty period.

Did not find your case?

Describe how it works on your side — we will tell you whether “Fondy integration” fits and what it means in your situation. No brief and no call: one question, one answer.

Cases

Tasks and results in numbers — all metrics measured by us

online store of professional tools, catalog of over 6,000 items

Task: See how many payment methods really survive until checkout and whether the payment step itself is safe.
Solution: External dimension without access to the project: checkout was performed as a buyer, response headers were removed, certificate was checked and redirects from the root were checked. The store works on another provider - the case is about the checkout itself, not about Fondy.
Result: Measurement 07/31/2026: 10 payment methods and 4 delivery methods - the widest set in our sample, including installments from two banks. Critical defect: Let's Encrypt certificate is valid, but https on bare domain returns 301 on http. Those who entered the address by hand see "Not protected" exactly where they enter the card.

online store of tactical equipment, catalog of more than 50,000 items

Task: Calculate what is visible about the payments in the reports of the big catalog.
Solution: External measurement 07/31/2026: site map with 32 product files, cross-checking with standard search, analysis of the payment page. The gateway at the store is different.
Result: 54,302 products and 635 categories, the difference between the two counting methods is 0.4%. Five methods of calculation, among them online installments with its own dataLayer event: the owner sees how many orders go this way, instead of guessing. First server response 413.8ms on this directory.

ProMakeup Opt

wholesale store of cosmetics for the beauty industry, catalog of almost 4,000 items

Task: Check out how wholesale checkout combines online payment with invoice and cash on delivery.
Solution: External measurement on July 31, 2026 according to the canonical site map and payment page. Online payment here goes through another provider.
Result: 3,947 products, 166 brands and 47 categories — 4,167 addresses in the site map, two consecutive measurements gave the same figure. In the checkout, there is an online gateway plus three alternative payment methods: cash on delivery, bank account, card.

MUEBLICA

online furniture store for the Spanish market

Task: Find out what the minimum payment is kept by a store that sells in another country.
Solution: External measurement 07/31/2026: the catalog was calculated by two independent sources, the payment terms page was viewed separately.
Result: Catalog of 76 products — the number coincided in the site map and in the standard search, the discrepancy is 0. There are exactly two methods of payment: online card and bank transfer. TTFB 348.2ms with 374KB markup. This kind of store is the reason to discuss multicurrency: the buyer is in another country, and the issue of the currency of the account arises from the first order.

Technologies & integrations

What we build on and what it connects to

Stack

Fondy API — card, several currencies and recurring in one gateway; limit: the list of currencies is set by your contract, not the site code
Verification of the signature of the answer - without it, the status "paid" can be set by a third party; this is the first thing we read in someone else's module
Recurring payments - the write-off itself is written in a day, and the balances around it eat up most of the term
OpenCart 3 / 4 — there are modules, but not every developer has a build for 4.x; we fix the version before the start
WooCommerce - plugins exist, some have not been updated for years; we take the one whose code has been read, not the one with more installations
Next.js and PHP — there is no ready-made module, we write API calls by hand; however, checkout is not limited to someone else's template
HTTPS + HSTS — mandatory at the payment step; the certificate encrypts the channel and does not make the site secure by itself

Integrations

Fondy
Visa/Mastercard
Apple Pay / Google Pay
multi-currency payments
regular write-offs
GA4 is a purchase event
KeyCRM

Add Fondy versus leaving the gateway that is already standing

How this option differs from the alternative

	Available gateway without modifications	Our approach
One-time payment in hryvnia	works already now, and it is not worth changing it for the sake of it	for the buyer, there is no difference - the commission and the convenience of the office decide
Payment in several currencies	often only the hryvnia: the buyer sees the recalculation and asks why the bank wrote off something else	the bill is issued in the currency of the script, if it is in your contract with the provider
Regular write-offs	most box modules do not have such logic at all	recursion with resume, cancellation, and retry handling
Buyer with a foreign card	depends on the provider's contract; part of the refusals comes from the side of the issuing bank	payment takes place in the interface familiar to the buyer, without going to another bank
What is it worth?	nothing: the gateway is already connected and paid for	one more commission and one more line on the accountant's monthly reconciliation

What we need from you

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

Seller ID and secret key from your account — the provider draws up the contract for you, not for the contractor.
Access to the site and admin with rights to install modules, plus a test environment if you have one.
A list of the currencies in which you plan to accept payment and the rule by which the invoice is issued.
A description of the subscription scenario, if required: frequency, failure behavior, cancellation method.
Legal texts about returns and subscription rules - they must be on the site before the first live payment.
An accountant for an hour or two: it is he who says in what form the reconciliation of receipts is needed.

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

We already accept the card - why another provider?

Often, there is no need, and we say so directly during the inspection. For a one-time payment in hryvnias, the difference between the gateways comes down to the commission and the convenience of the office, and the second provider adds another line to the monthly reconciliation. The conversation becomes substantive when a scenario appears that the existing gateway does not handle: an invoice in euros for a buyer from the EU, a monthly debit for access, a refund of part of the amount from the admin account. Then the question is no longer "which gateway is better", but "what exactly should happen after pressing the button".

Why can't the order status be set on the "thank you" page?

Because this page depends on the buyer's browser, not money. The person paid in the banking application and returned to it, not to the browser; lost the network in the elevator; closed the tab immediately after writing off. The money is gone, the status remains. That's right: the gateway sends a response to your server, the server checks the signature and sets the status itself. We write the processor idempotent by the order number — a repeated response to the same order does not create a second record and does not send the buyer a second letter. And separately, we add a repeated status request from the server, if the answer did not come within the specified time.

What's really hard about subscriptions?

Not a write-off. Write-off is one API call, it is written per day. Complex all around: continuation, cancellation by the buyer in one step, unsuccessful charge-off due to lack of funds and deciding how many times to try again, changing the card without losing the subscription, a letter at each of these steps. Plus separate statuses in orders so that the manager understands what is happening and the picture is clear for the accountant. When they ask you to "just connect the subscription", they usually mean just that one call - and the rest is work.

Can I display prices in multiple currencies?

Yes, if multi-currency is provided by your contract with the provider. Technically, the question is different: what does the buyer see. We display the amount in the currency in which the invoice is actually issued, and write a note about the conversion next to it. The reason is simple - the bank will write off exactly the amount that is in the account, and if there was a different number on the website, the first thing the buyer will do is write to you. The furniture store we measured for the Spanish market has only two methods of payment — card and transfer; for one country this is enough, for several markets the issue of currency emerges immediately.

How safe is it to keep provider keys on the site?

They are only as safe as they are handled carefully. We keep the secret key in the environment variables, not in the theme config: otherwise it goes to the repository, to the backup, and to everyone who once had access to the files. The second is HTTPS all the way to checkout. Here it's useful to look at a finding from our tool store dimension: the certificate is valid, and login to the bare domain returns a 301 to insecure HTTP, and the browser shows "Not Secure" on the card input step. A fair boundary: the certificate encrypts the channel and does not make the site secure by itself - an outdated CMS or PHP without support remains a separate task.

How long does the work last and why is the sum of days by stage greater than the deadline?

The term is 7–14 working days. By stages: script verification 1–2 days, gateway and callback 1–3, currencies and amount display 1–2, subscriptions with all states 3–6, live payment and transfer 1. The amount looks larger, because the subscription stage is not always enabled, and part of the work goes on in parallel: while we are waiting for the combat keys, the handler is already being written on the test ones. The lower limit of 4 days is realistic for a one-time payment when accesses are available from the first day.

Do you have a case on this particular gateway?

No. The stores we measured accept payment through other providers, and passing them off as a Fondy case would be a rip-off. The cases on this page are our measurements of checkouts from 07/31/2026: they show which set of payment methods make it to the payment page, how many are in a wide checkout, and what breaks at this step. Instead of a fictitious case, we offer to check your checkout for free and show the findings on your own website - this is a more honest proof than someone else's success story.

Advice from you: how to start when half of the orders are in "pending payment"?

Not from the new gateway. First, open the provider's account and compare the number of successful payments per week with the number of orders in the "paid" status on the site. If there are more payments in the office, the problem is not in receiving money, but in how the site learns about it, and the second provider will only double it. Our best practice recommendation is that it costs a few days to fix the gateway response processing, and a new integration on top of the broken logic costs the same days plus one more fee every month.

Submit the payment page address and describe the scenario in one paragraph

In 1-2 working days, we will return with an analysis: what your checkout gives to the buyer now, which scenario makes sense to enable and how much work it is. If the task is closed by a gateway that you already have, you will hear it in the first email.

From measured cases54,302 products and 635 categories, the difference between the two counting methods is 0.4%

View cases

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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.

Fondy integration: payments and subscriptions on the site

Free check before connecting the gateway

What we measure

What you get

Why is it free

What's next

We work officially

Contract, act and 30-day warranty

Sole proprietor & bank transfer

Rights & access — yours

Client portal instead of email chains

Sites in nine countries

Verifiable numbers

Audit first, then pricing

We say "no" when unsure