| Document and Entity Information | Nov. 08, 2021 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 8, 2021 |
| Entity Registrant Name | eFFECTOR Therapeutics, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39866 |
| Entity Tax Identification Number | 85-3306396 |
| Entity Address, Address Line One | 11120 Roselle Street |
| Entity Address, Address Line Two | Suite A |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92121 |
| City Area Code | 858 |
| Local Phone Number | 925-8215 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001828522 |
| Common stock, $0.0001 par value per share [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Common stock, $0.0001 par value per share |
| Trading Symbol | EFTR |
| Security Exchange Name | NASDAQ |
| Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Warrants to purchase common stock |
| Trading Symbol | EFTRW |
| Security Exchange Name | NASDAQ |
