| Cover | Apr. 21, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Entity Registrant Name | Backblaze, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-41026 |
| Entity Tax Identification Number | 20-8893125 |
| Entity Address, Address Line One | 500 Ben Franklin Ct |
| Entity Address, City or Town | San Mateo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94401 |
| City Area Code | 650 |
| Local Phone Number | 352-3738 |
| 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 $0.0001 per share |
| Trading Symbol | BLZE |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001462056 |
| Amendment Flag | false |
| Document Period End Date | Apr. 21, 2022 |
