Regex (Regular Expressions) filters are a powerful way to customize your feeds by including or excluding content based on specific patterns.

Understanding Regex Filters

Regex filters allow you to:

Include specific posts: Show only posts that match certain patterns.
Exclude specific posts: Hide posts that match certain patterns.
Modify feed content dynamically: Match patterns in titles, descriptions, or other fields.

Regex Operators and Syntax Table

Operator/Syntax	Description	Example	Explanation
`.`	Matches any single character except a newline.	`a.b`	Matches `aab`, `acb`, but not `ab` or `a\nb`.
`*`	Matches 0 or more repetitions of the preceding element.	`ab*`	Matches `a`, `ab`, `abb`, `abbb`.
`+`	Matches 1 or more repetitions of the preceding element.	`ab+`	Matches `ab`, `abb`, `abbb`, but not `a`.
`?`	Matches 0 or 1 repetition of the preceding element.	`colou?r`	Matches `color` or `colour`.
`	`	OR operator (matches either pattern).	`cat
`^`	Matches the start of a string.	`^Hello`	Matches `Hello` only at the beginning of the string.
`$`	Matches the end of a string.	`world$`	Matches `world` only at the end of the string.
`[]`	Matches any one character in the brackets.	`[abc]`	Matches `a`, `b`, or `c`.
`[^]`	Matches any one character not in the brackets.	`[^abc]`	Matches any character except `a`, `b`, or `c`.
`()`	Groups expressions. Used for capturing.	`(ab)+`	Matches `ab`, `abab`, `ababab`. Captures each repetition.
`{n}`	Matches exactly `n` repetitions.	`a{3}`	Matches `aaa`.
`{n,}`	Matches `n` or more repetitions.	`a{2,}`	Matches `aa`, `aaa`, `aaaa`, etc.
`{n,m}`	Matches between `n` and `m` repetitions.	`a{2,4}`	Matches `aa`, `aaa`, or `aaaa`.
`\`	Escapes a special character.	`\.`	Matches the literal `.` character.
`\d`	Matches any digit (0–9).	`\d+`	Matches `123`, `456`, etc.
`\D`	Matches any non-digit.	`\D+`	Matches `abc`, `@#$`, etc.
`\w`	Matches any word character (letters, digits, underscore).	`\w+`	Matches `hello`, `word_1`, etc.
`\W`	Matches any non-word character.	`\W+`	Matches `@#$`, (space), etc.
`\s`	Matches any whitespace character.	`\s+`	Matches spaces, tabs, or newlines.
`\S`	Matches any non-whitespace character.	`\S+`	Matches words or symbols, but not spaces.

Common Use Cases

Remove Unwanted Characters or Text

Remove specific parts of a title or description.

Example:

Pattern: ^(.*?)\s—.*
Result: Matches the first part of a title before the — symbol and removes everything after it.
Use Case: Clean titles like Breaking News — World Updates to only show Breaking News.

Whitelist Specific Keywords

Include posts that contain specific words or phrases.

Example:

Pattern: .*(AI|Machine Learning|Data Science).*
Result: Matches posts containing AI, Machine Learning, or Data Science.
Use Case: Curate a feed with only tech-related content.

Blacklist Specific Keywords

Exclude posts with unwanted words or phrases.

Example:

Pattern: .*(Sports|Celebrity|Gossip).*
Result: Hides posts containing Sports, Celebrity, or Gossip.
Use Case: Avoid non-business-related content.

Filter by URL or Domain

Use regex to include or exclude posts from specific domains.

Example:

Pattern: .*example\.com.*
Result: Filters posts that mention example.com in the URL.
Use Case: Target posts from a specific website.

Match Specific Date Formats

Include or exclude posts based on date formats.

Example:

Pattern: \d{4}-\d{2}-\d{2}
Result: Matches a date format like 2024-12-31.
Use Case: Focus on posts with structured date formats.

How to Apply Regex Filters

Navigate to the feed/bundle filters you want to apply the filter to.
Go to Replace or Remove and Add Replace/Remove rule
Enable Regular expression by clicking on .*
Add Regex Pattern: .*example\.com.*

Troubleshooting

Double-check your regex syntax and ensure it matches the target content.
Ensure no conflicting filters are applied.

Example Scenarios

Replace specific hashtags with a keyword

Use case: Replace "#AI" and "#MachineLearning" with "Technology".
Filter type: Replace
Regex: #(AI|MachineLearning)

Replace emoji with text

Use case: Replace all emojis with the text [EMOJI].
Filter type: Replace
Regex: [^\w\s,.!?]

Remove bold from title or description

Use case: Remove bold formatting from titles
Filter type: Remove
Regex: <\/?b>

Replace certain text patterns

Use case: Replace "Breaking News:" with "[Updated]".
Filter type: Replace
Regex: ^Breaking News:

Replace company name in titles

Use case: Replace "RSS.app" with "Our Service".
Filter type: Replace
Regex: RSS\.app

Remove text after a specific delimiter

Use case: Remove everything after a "—" in a title.
Filter type: Remove
Regex: —.*

Remove URLs from content

Use case: Remove all URLs from feed descriptions.
Filter type: Remove
Regex: https?://[^\s]+

Remove special characters

Use case: Remove all non-alphanumeric characters except spaces.
Filter type: Remove
Regex: [^a-zA-Z0-9\s]

Remove titles starting with specific keywords

Use case: Remove all posts with titles starting with "Promo" or "Ad".
Filter type: Remove
Regex: ^(Promo|Ad).*

Remove trailing hashtags

Use case: Remove hashtags at the end of a title.
Filter type: Remove
Regex: \s#[\w]+$

Remove numbers from text

Use case: Remove all digits from descriptions.
Filter type: Remove
Regex: \d+

💡Tips

Use tools like Regex101 to validate your regex patterns before applying them.
Begin with basic patterns and refine as you understand how they affect your feed.
If you're having trouble creating a regex pattern, you can use AI tools like ChatGPT to assist you. Simply describe what you're trying to filter or match, and it can generate the necessary regex filter for you.