| Cover Page | Oct. 30, 2019 |
| Entity Addresses [Line Items] | |
| Entity Address, Address Line One | 101 Spear Street |
| Entity Address, Address Line Two | Suite 300 |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94105 |
| Document Type | 8-K |
| Document Period End Date | Oct. 30, 2019 |
| Entity Registrant Name | Twilio Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37806 |
| Entity Tax Identification Number | 26-2574840 |
| City Area Code | 415 |
| Local Phone Number | 390-2337 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, par value $0.001 per share |
| Trading Symbol | TWLO |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Former Address | |
| Entity Addresses [Line Items] | |
| Entity Address, Address Line One | 375 Beale Street |
| Entity Address, Address Line Two | First Floor |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94105 |
| Cover Page Non-Printing | Oct. 30, 2019 |
| Cover Page [Abstract] | |
| Entity Central Index Key | 0001447669 |
| Amendment Flag | false |
