Connect Adyen

Who this is for

Adyen is an enterprise processor. It prices on Interchange++, which is the cheapest arrangement available once you are doing serious volume, and it supports essentially every local payment method in the world.

It is also the only provider in kitty that you cannot simply sign up for. Adyen approves merchants individually and expects meaningful volume before it will talk terms. If you are just starting out, connect something else and come back to this when the numbers justify it — the card says as much.

Before you start

An approved Adyen merchant account, and access to the Customer Area.

Where to get the four values

Adyen API key — Customer Area → Developers → API credentials → your web-service user → API key. Generate one and copy it; it is shown once.

Merchant account — the account code, not your company account name. Adyen gives you a company account with one or more merchant accounts underneath it, and this is the one underneath. It appears in the Customer Area's account switcher.

HMAC key — Customer Area → Developers → Webhooks → your standard webhook → Generate HMAC key. Point that same webhook at the URL kitty gives you (see below). This key is what proves an incoming notification is genuinely Adyen's.

Live URL prefix — Customer Area → Developers → API URLs. Leave this blank to stay on Adyen's test environment; fill it in when you go live. It looks like a random string followed by your company name.

Connecting

Settings → Connections → Take payments → the Adyen card → Connect → fill the fields → Save and connect, then Test connection, which confirms the key reaches the merchant account you named.

The webhook, which is not optional

kitty needs Adyen to tell it when someone pays. Without that, the checkout takes the money and no order, customer or revenue figure ever appears in kitty.

On the connected card, press Webhook URL, copy it, and paste it into Customer Area → Developers → Webhooks as the URL of your standard webhook.

Treat that URL like a password — anyone holding it can post events at this venture. It never expires; you rotate it by disconnecting and reconnecting. Deliveries are capped at 300 a minute per venture.

Two things kitty checks that others do not

Adyen sends notifications in batches. kitty verifies every item in the batch separately, so one forged item cannot ride in on its neighbours' valid signatures. It also refuses any notification whose merchant account is not the one you connected.

What it can and cannot do here

One-off card payments, with chargebacks reported and noted on the order. No subscriptions and no failed-payment recovery through kitty; refunds are issued in the Customer Area and recorded here when reported.

Adyen's Pay by Link is reusable, so a buy button points straight at Adyen with no extra hop.

After it's connected

Test connection proves the key works right now, and names the account it reached — so a member with two logins can see they pasted the wrong one. Do that before you put anything on sale.

Then, in Where new checkouts go, pick this provider on its own or One page, every method, which offers every provider you've connected on a single page and quietly hides one that starts failing.

Anything already on sale keeps the provider it was armed on. A price, once created at a provider, cannot be moved — so to switch, open the venture's Revenue tab, Take off sale, then put it back on sale.

How the keys are stored

Encrypted at rest with AES-256-GCM, used server-side only, never returned to the browser, never written to a log, and never shown again after saving.

Payment keys are scoped to a venture or the whole workspace, never to you personally — two businesses in one workspace settle into two different bank accounts, so a personal key is refused for money on purpose.