| allow_null | Allow NULL |
| as_contract_block | Convert a Validator to a Multi-Line Block |
| as_contract_text | Convert a Validator to Plain Text |
| expect_invalid | Expect a Value to Fail a Validator |
| expect_valid | Expect a Value to Pass a Validator |
| fail | Format a Validation Error |
| is_valid | Test Whether a Value Satisfies a Validator |
| require_any | Require at Least One of Several Validators |
| require_between | Require Value in Range |
| require_character | Require Character Type |
| require_class | Require a Specific Class |
| require_col | Validate a Data Frame Column with a Validator |
| require_contains | Require All of a Set of Values |
| require_custom | Create a Custom Validation Step |
| require_df | Require a Data Frame |
| require_dim | Require Exact Dimensions |
| require_dir_exists | Require Existing Directories |
| require_disjoint | Require Values Disjoint From Context |
| require_each | Validate Every Element of a List |
| require_fields | Validate Named Fields of a List |
| require_file_exists | Require Existing Files |
| require_finite | Require Finite Values |
| require_function | Require a Function |
| require_has_cols | Require Specific Columns |
| require_integer | Require Integer Values |
| require_length | Require Specific Length |
| require_length_matches | Require Length Matching an Expression |
| require_length_max | Require Maximum Length |
| require_length_min | Require Minimum Length |
| require_levels | Require Factor Levels |
| require_logical | Require Logical Type |
| require_named | Require Named Value |
| require_names | Require Names |
| require_nchar | Require String Length |
| require_ncol_matches | Require Column Count Matching an Expression |
| require_ncol_min | Require Minimum Number of Columns |
| require_negative | Require Negative Values |
| require_nonempty | Require Non-Blank Strings |
| require_not_null | Require Non-NULL Value |
| require_no_na | Require No NA Values |
| require_nrow_matches | Require Row Count Matching an Expression |
| require_nrow_min | Require Minimum Number of Rows |
| require_numeric | Require Numeric Type |
| require_one_of | Require Value from a Set |
| require_pattern | Require Strings Matching a Pattern |
| require_positive | Require Positive Values |
| require_readable | Require Readable Paths |
| require_scalar | Require Scalar Value |
| require_set_equal | Require the Same Set of Values |
| require_sorted | Require Sorted Values |
| require_unique | Require Unique Values |
| require_unique_names | Require Unique Names |
| require_valid | Include Another Validator's Steps |
| require_writable | Require Writable Paths |
| restrict | Create a Composable Validator |
| steps | List the Steps of a Validator |
| validation_errors | Collect Validation Errors Without Throwing |