--- title: "Checkout integration for developers · Fungies" description: "Hosted page, overlay modal or embedded frame. The same checkout in all three — what differs is where it renders and how much of the flow you own." image: "https://fungies.io/og-image.jpg" canonical: "https://fungies.io/best-checkout-integration/" --- Developers · Choosing an integration # Three ways to wire checkout into an app you already have The decision is not about features. The checkout is the same object in all three modes: the same certified payment surface, the same tax handling, the same rate. What changes is where it renders, how much of the surrounding experience is yours to build, and what you are agreeing to maintain. [Start free](https://app.fungies.io/register) [Book a demo](https://calendly.com/duke-vuh/fungies-io-demo-clone) No upfront costs. No credit card required. Already selling with Fungies [![Leadsin.io](/logos/clients/leadsin.png)](/customer-story/hosted-checkout-solution-for-leadsin-io-a-saas-business "Leadsin.io — read the story")[![RenderAI](/logos/clients/renderai.png) ](/customer-story/helping-renderai-reduce-their-ai-saas-payment-integration-from-days-to-just-a-couple-of-minutes "RenderAI — read the story")[![SuperScale](/logos/clients/superscale.png) ](/customer-story/nimblebits-revenue-boost-with-a-web-store-solution "SuperScale — read the story")[![FreeVocals](/logos/clients/freevocals.png) ](/customer-story/freevocals-com-and-fungies-io-a-seamless-solution-for-digital-e-commerce "FreeVocals — read the story")![STATSCORE](/logos/clients/statscore.png)![SimFabric](/logos/clients/simfabric.png)![BotRix](/logos/clients/botrix.png)![Enhance AI](/logos/clients/enhance-ai.png)![The Humanize AI](/logos/clients/humanize-ai.png)![Kenerate AI](/logos/clients/kenerate.png) ![A Fungies checkout rendered inline in a page, showing a subscription line, billing details, card fields, a bank option and Google Pay.](/_astro/embedded-checkout.BrKPrL7H_1BsxIb.webp?dpl=dpl_8EZJmbvb3ugYq7WK1KgC21BX19Zp) The embedded mode: the same checkout, drawn inside a layout you own. ## What is identical whichever mode you ship The payment surface Card fields render inside a frame we serve and certify. In all three modes nothing sensitive enters your DOM, your logs or your infrastructure, so none of this reaches your compliance scope. Tax and the seller of record We are the legal seller wherever the checkout is drawn. The rate for the buyer's country is applied, then remitted and filed under our registrations. Where the modal opens does not change who is liable. Method selection The methods offered are picked from the buyer's country and the charging currency, not from a list you configure per integration. A Dutch buyer sees iDEAL in an embedded frame just as they would on the hosted page. The things you pass in Billing prefill, a discount code, a quantity, several offers at once, and your own custom fields — user ID, seat, server region — readable back off the order afterwards. The signal that money arrived The payment\_success webhook fires the same way from all three. The browser also emits fungies:checkout:complete, which is for redirecting the buyer, not for granting them anything. Sandbox and test payments A full purchase, including a subscription renewal, can be run end to end before a real card is charged. That applies to whichever mode you are evaluating. ## The integration, step by step 1. 01 ### Build a checkout element Configure it once in the dashboard — the offers it sells, how it looks — and you get a URL. Elements can also be created through the REST API if you would rather generate them. 2. 02 ### Point something at that URL Link to it, put it on a button with data-fungies-checkout-url and load the SDK script, or nominate an element for it to render into. That choice is the mode. 3. 03 ### Send what you already know Prefill the email and country of a signed-in user, pass the discount that was on the page, and attach the identifiers your own system will need to match the order to an account. 4. 04 ### Fulfil from the server Grant access on payment\_success rather than on the browser event. A tab can be closed before any client-side callback runs, and the webhook cannot be. ## Picking one, and what it costs you 01 ### Hosted — no integration, at the price of a redirect A URL is the whole thing. Nothing to deploy, nothing on your side to keep patched, and it works from a Discord message or an email where you own no surface at all. The cost is that you hand the buyer to a page you did not lay out, and someone who abandons it comes back to a browser history entry rather than to the page that convinced them. 02 ### Overlay — keeps the page, adds a script tag The modal opens over the page the buyer is reading and the address bar never changes. The cost is real but small: a script tag, and a call to Fungies.ScanDOM() if your framework renders buy buttons after first paint. You also own how a modal behaves on a narrow screen, which is worth testing rather than assuming. 03 ### Embedded — most control, most of your code The checkout renders inline inside a flow you designed, which suits an onboarding step or an in-app upgrade that should not break stride. The cost is that everything around the frame is yours: the layout, the responsive behaviour, and the state your page is in while a payment is pending. 04 ### You are allowed more than one A link in the renewal email, an overlay on the pricing page and an embedded frame inside onboarding can all point at the same offers. They produce one catalogue, one order list and one payout stream, and the rate is 5% + 50¢ in every case. Negotiable once you are selling at volume. ## What sellers say once they have switched [★★★★★ 4.8/5 from 10 reviews on G2 →](https://www.g2.com/products/fungies-io/reviews) [Vadim Finayev Head of Growth, Leadsin.io “We work with quite a few merchants of record, but none comes close to the support and speed of implementation of Fungies. If you want a payment partner that actually gives you the feeling they want to work with you — rather than leaving you on read for three days or randomly restricting your account — you are in the right place.” Read the story →](/customer-story/hosted-checkout-solution-for-leadsin-io-a-saas-business) [David Elliott Creative Director, Freevocals.com “I researched the options and Fungies was the best fit for functionality and customisation within a store builder you can connect to your own domain. Taking a small percentage of sales, instead of charging a subscription for every environment and plugin, is refreshing.” Read the story →](/customer-story/freevocals-com-and-fungies-io-a-seamless-solution-for-digital-e-commerce) [Elnura Abdimanap Kyzy Founder, TextToVideo.bot “The platform is user-friendly, integrates easily with APIs and webhooks, and simplifies managing digital products and subscriptions. We were up and running quickly and support has been responsive throughout. Fungies is clearly tailored to the needs of SaaS businesses.” Read the story →](/customer-story/how-fungies-enabled-texttovideo-bot-to-integrate-payments-in-minutes) [Francisco Magnone Rienzi Founder, Renderai.app “Fungies has been a great partner — fast setup, competitive pricing, and real humans providing quick answers. They are constantly rolling out new features, and I am excited to see what is next.” Read the story →](/customer-story/helping-renderai-reduce-their-ai-saas-payment-integration-from-days-to-just-a-couple-of-minutes) ## Before you commit to a mode ### Which mode converts best? ### Can I change my mind later without touching the catalogue? ### Do I need the JavaScript SDK? ### How do I match a payment back to a user in my database? ### Does a deeper integration cost more? Checkout ## The three ways to put a payment surface in front of a buyer. - [Hosted Checkout →](/hosted-checkout) - [WooCommerce Stripe Payment Gateway →](/woocommerce-stripe-payment-gateway) ## Test all three before choosing Build one checkout element, open it as a link, as an overlay and as an embedded frame, and run a sandbox purchase through each. That takes an afternoon and settles the argument with your own product in front of you. [Start free](https://app.fungies.io/register) [Book a demo](https://calendly.com/duke-vuh/fungies-io-demo-clone) No upfront costs. No credit card required. ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://fungies.io/#organization","name":"Fungies","legalName":"Fungies Inc.","url":"https://fungies.io/","description":"Merchant of Record for SaaS, games, and digital products. Fungies handles global payments, VAT and sales tax, and checkout. Free to start, commission only.","slogan":"Tax-compliant payments for everything digital","logo":{"@type":"ImageObject","url":"https://fungies.io/brand/fungies-logo-black.svg"},"image":"https://fungies.io/og-image.jpg","address":{"@type":"PostalAddress","streetAddress":"2100 Geng Road, Suite 210","addressLocality":"Palo Alto","addressRegion":"CA","postalCode":"94303","addressCountry":"US"},"sameAs":["https://www.facebook.com/fungies.io","https://www.linkedin.com/company/fungies","https://twitter.com/fungies_io","https://t.me/fungies_announcements","https://discord.gg/yfH5ZyTZH4","https://www.youtube.com/@Fungies","https://www.tiktok.com/@fungies_io"],"contactPoint":[{"@type":"ContactPoint","contactType":"customer support","email":"support@fungies.io","url":"https://help.fungies.io/","availableLanguage":["en"]}]},{"@type":"WebSite","@id":"https://fungies.io/#website","name":"Fungies","url":"https://fungies.io/","description":"Merchant of Record for SaaS, games, and digital products. Fungies handles global payments, VAT and sales tax, and checkout. Free to start, commission only.","inLanguage":"en","publisher":{"@id":"https://fungies.io/#organization"}},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://fungies.io/"},{"@type":"ListItem","position":2,"name":"Checkout integration for developers","item":"https://fungies.io/best-checkout-integration"}]},{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"Which mode converts best?","acceptedAnswer":{"@type":"Answer","text":"We will not give you a number, because the honest answer depends on your product and your traffic. The mechanic that differs is whether the buyer leaves the page they were persuaded on. Ship one, watch abandoned carts in the dashboard, and change it — the mode is a setting on the element, not a rewrite."}},{"@type":"Question","name":"Can I change my mind later without touching the catalogue?","acceptedAnswer":{"@type":"Answer","text":"Yes. Products, offers and the checkout element stay as they are; the mode is how you open the same URL. Moving from hosted to overlay is a button attribute, and moving to embedded is nominating a container."}},{"@type":"Question","name":"Do I need the JavaScript SDK?","acceptedAnswer":{"@type":"Answer","text":"Only if a button is not enough. The data attributes cover a static site, WordPress, Webflow or a hand-written page. Install @fungies/fungies-js when you want to open checkout programmatically or pass values you compute at runtime."}},{"@type":"Question","name":"How do I match a payment back to a user in my database?","acceptedAnswer":{"@type":"Answer","text":"Custom fields. Send your own user ID through the checkout and read it off the order in the webhook payload. That is more reliable than matching on email, which a buyer can change at the payment step."}},{"@type":"Question","name":"Does a deeper integration cost more?","acceptedAnswer":{"@type":"Answer","text":"No. The API, the webhooks, the SDK, the CLI and the MCP server are all included, and every mode is charged at the same flat 5% + 50¢ per successful transaction with no platform fee underneath it. Negotiable once you are selling at volume."}}]}]} ```