| Cover | Aug. 17, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 17, 2021 |
| Entity Registrant Name | Outbrain Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40643 |
| Entity Tax Identification Number | 20-5391629 |
| Entity Address, Address Line One | 111 West 19th Street |
| Entity Address, City or Town | New York, |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10011 |
| City Area Code | (646) |
| Local Phone Number | 859-8594 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, par value $0.001 per share |
| Trading Symbol | OB |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Amendment Flag | false |
| Entity Central Index Key | 0001454938 |
| Entity Ex Transition Period | false |
