| Document and Entity Information | Aug. 09, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001477333 |
| Document Type | 8-K |
| Document Period End Date | Aug. 9, 2021 |
| Entity Registrant Name | Cloudflare, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39039 |
| Entity Tax Identification Number | 27-0805829 |
| Entity Address, Address Line One | 101 Townsend Street |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94107 |
| City Area Code | (888) |
| Local Phone Number | 993-5273 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A Common Stock, par value $0.001 per share |
| Trading Symbol | NET |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
