dig internal-api.monzo.com
    
    ;; QUESTION SECTION:
    ;internal-api.monzo.com.  IN A
    
    ;; ANSWER SECTION:
    internal-api.monzo.com. 288 IN CNAME k8s-worker-external-alb-prod-1306866561.eu-west-1.elb.amazonaws.com.
    k8s-worker-external-alb-prod-1306866561.eu-west-1.elb.amazonaws.com. 8 IN A 34.254.57.66
    k8s-worker-external-alb-prod-1306866561.eu-west-1.elb.amazonaws.com. 8 IN A 52.212.7.167
    k8s-worker-external-alb-prod-1306866561.eu-west-1.elb.amazonaws.com. 8 IN A 34.255.246.8
    

Monzo the bank, runs from Amazon and not via Cloudflare.

    dig www.monzo.com
    
    ;; QUESTION SECTION:
    ;www.monzo.com.   IN A
    
    ;; ANSWER SECTION:
    www.monzo.com.  59 IN A 104.25.212.99
    www.monzo.com.  59 IN A 104.25.211.99
    

Monzo the marketing website for the bank, uses Cloudflare.

If you go through the DNS logs for the Monzo app, you'll see everything else goes direct... Google, Facebook, Status Page, AWS.

With the only exception being some image assets:

    dig monzo-prod-user-images.imgix.net
    
    ;; QUESTION SECTION:
    ;monzo-prod-user-images.imgix.net. IN A
    
    ;; ANSWER SECTION:
    monzo-prod-user-images.imgix.net. 2280 IN CNAME dualstack.com.imgix.map.fastly.net.
    dualstack.com.imgix.map.fastly.net. 4 IN A 151.101.18.208