R: Vignettes and other documentation

# Vignettes and other documentation

## Vignettes from package 'crul'

crul::async |  | 3. async with crul | HTML | source |
crul::best-practices-api-packages |  | 5. API package best practices | HTML | source |
crul::choosing-a-client |  | 6. Choosing a HTTP request class | HTML | source |
crul::crul |  | 1. crul introduction | HTML | source |
crul::curl-options |  | 4. curl options | HTML | source |
crul::how-to-use-crul |  | 2. crul workflows | HTML | source |