| Document and Entity Information | Nov. 05, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001657573 |
| Document Type | 8-K |
| Document Period End Date | Nov. 5, 2021 |
| Entity Registrant Name | Xometry, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40546 |
| Entity Tax Identification Number | 32-0415449 |
| Entity Address, Address Line One | 7529 Standish Place |
| Entity Address, Address Line Two | Suite 200 |
| Entity Address, City or Town | Derwood |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20855 |
| City Area Code | 240 |
| Local Phone Number | 335-7914 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A Common Stock, $0.000001 par value per share |
| Trading Symbol | XMTR |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
