| Document and Entity Information | Apr. 12, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001666071 |
| Document Type | 8-K |
| Document Period End Date | Apr. 12, 2021 |
| Entity Registrant Name | CARDLYTICS, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38386 |
| Entity Tax Identification Number | 26-3039436 |
| Entity Address, Address Line One | 675 Ponce de Leon Avenue NE |
| Entity Address, Address Line Two | Suite 6000 |
| Entity Address, City or Town | Atlanta |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 30308 |
| City Area Code | (888) |
| Local Phone Number | 798-5802 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock |
| Trading Symbol | CDLX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
