DevelopersTools
SDKs
The seven Fianto packages, what each one is for, and which to install for Next.js, Express, Hono or a plain page.
Fianto ships seven TypeScript packages. One is the API client that runs on your server, three wrap its route handlers for a web framework, two open checkout in the browser, and one is a command line for development. Every package is version 0.1.0 and needs Node.js 20.3 or later. The six library packages ship as ESM and CommonJS; the CLI is ESM only.
The packages
| Package | What it is for | Runs on | Peer dependency |
|---|---|---|---|
@fianto/sdk | The typed API client, webhook verification (/webhooks) and framework-free route handlers (/handlers) | Your server | — |
@fianto/nextjs | Webhooks() and Checkout() as App Router route handlers | Your server | next 15 or later (optional) |
@fianto/express | webhooks() and checkout() as Express middleware | Your server | express 4 or later |
@fianto/hono | webhooks() and checkout() as Hono handlers | Your server | hono 4 or later |
@fianto/js | openCheckout, redirectToCheckout and the <fianto-button> element | The browser | — |
@fianto/react | useCheckout and FiantoButton | The browser (React) | react 19 or later |
@fianto/cli | The fianto command: signed samples, event forwarding, whoami | Your machine or CI | — |
The server packages hold your app secret. new Fianto() throws when it runs in a browser, and there
is no publishable key: your server always creates the checkout session, and the browser packages
only open the page your server created.
Which to install
Each stack needs a server package for the checkout and webhook routes, and a browser package for the pay button.
# Next.js
pnpm add @fianto/nextjs @fianto/react @fianto/sdk
# Express
pnpm add @fianto/express @fianto/js @fianto/sdk
# Hono
pnpm add @fianto/hono @fianto/js @fianto/sdk
# Any other server: the client and the framework-free handlers
pnpm add @fianto/sdkEach line adds @fianto/sdk next to the adapter, so your own code can import Fianto and the
webhook helpers from it. Run the CLI without installing it: npx @fianto/cli whoami.
Runtimes
Tested on Node.js, designed for more
CI tests the SDK on Node.js 22 and 24 and smoke-tests the built @fianto/sdk on Node.js 20.3.0. @fianto/sdk, @fianto/nextjs and @fianto/hono use only fetch and Web Crypto in the request
path, so they are designed for Vercel Edge, Cloudflare Workers, Bun and Deno too, but those runtimes
are not tested yet. @fianto/express is for Node.js: it reads Express's Node request stream.
On Cloudflare Workers there is no process.env: pass your secrets to the handlers yourself. The
Hono page shows how.
Where to go next
@fianto/sdk
Options, resources, errors and retries.
Next.js
Webhooks() and Checkout() route handlers.
Express
Mount order, body size and proxies.
Hono
Node and Cloudflare Workers.
Browser
openCheckout and the fianto-button element.
React
useCheckout and the FiantoButton component.
See also
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