| Document and Entity Information | Nov. 12, 2019 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 12, 2019 |
| Entity Registrant Name | CARDLYTICS, INC. |
| Entity Central Index Key | 0001666071 |
| Entity Emerging Growth Company | true |
| Entity Incorporation, State or 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, 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 |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | CDLX |
| Security Exchange Name | NASDAQ |
| Entity Ex Transition Period | false |
