| Document and Entity Information | Dec. 02, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001626450 |
| Document Type | 8-K |
| Document Period End Date | Dec. 2, 2021 |
| Entity Registrant Name | BigCommerce Holdings, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39423 |
| Entity Tax Identification Number | 46-2707656 |
| Entity Address, Address Line One | 11305 Four Points Drive |
| Entity Address, Address Line Two | Building II |
| Entity Address, Address Line Three | Third Floor |
| Entity Address, City or Town | Austin |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 78726 |
| City Area Code | (512) |
| Local Phone Number | 865-4500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Series 1 Common Stock, $ 0.0001 par value per share |
| Trading Symbol | BIGC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
