| Cover | Apr. 18, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 18, 2022 |
| Entity Registrant Name | Blend Labs, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40599 |
| Entity Tax Identification Number | 45-5211045 |
| Entity Address, Address Line One | 415 Kearny Street |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94108 |
| City Area Code | 650 |
| Local Phone Number | 550-4810 |
| 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 of $0.00001 per share |
| Trading Symbol | BLND |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001855747 |
