Filters

Filters let you block or flag content based on specific words, domains, emails, or regex patterns. To use filters in moderation, you first create a blocklist, then attach it to a moderation policy.

Create a Blocklist

Create a custom blocklist with a name, type, and list of entries.

// Create a word blocklist
await client.createBlockList({
  name: "profanity_custom",
  words: ["badword1", "badword2", "offensive"],
  type: "word",
});

// Create a domain blocklist
await client.createBlockList({
  name: "blocked_domains",
  words: ["spam-site.com", "phishing.net"],
  type: "domain",
});

// Create a regex filter
await client.createBlockList({
  name: "phone_numbers",
  words: ["\\b\\d{3}[-.]?\\d{3}[-.]?\\d{4}\\b"],
  type: "regex",
});

// Create a domain allowlist (only these domains are permitted)
await client.createBlockList({
  name: "trusted_domains",
  words: ["myapp.com", "getstream.io"],
  type: "domain_allowlist",
});

// Create an email allowlist
await client.createBlockList({
  name: "approved_emails",
  words: ["support@myapp.com", "info@myapp.com"],
  type: "email_allowlist",
});

# Create a word blocklist
client.create_block_list(
    name="profanity_custom",
    words=["badword1", "badword2", "offensive"],
    type="word",
)

# Create a domain blocklist
client.create_block_list(
    name="blocked_domains",
    words=["spam-site.com", "phishing.net"],
    type="domain",
)

# Create a regex filter
client.create_block_list(
    name="phone_numbers",
    words=["\\b\\d{3}[-.]?\\d{3}[-.]?\\d{4}\\b"],
    type="regex",
)

# Create a domain allowlist (only these domains are permitted)
client.create_block_list(
    name="trusted_domains",
    words=["myapp.com", "getstream.io"],
    type="domain_allowlist",
)

# Create an email allowlist
client.create_block_list(
    name="approved_emails",
    words=["support@myapp.com", "info@myapp.com"],
    type="email_allowlist",
)

// Create a word blocklist
client.CreateBlockList(ctx, &getstream.CreateBlockListRequest{
    Name:  "profanity_custom",
    Words: []string{"badword1", "badword2", "offensive"},
    Type:  getstream.PtrTo("word"),
})

// Create a domain blocklist
client.CreateBlockList(ctx, &getstream.CreateBlockListRequest{
    Name:  "blocked_domains",
    Words: []string{"spam-site.com", "phishing.net"},
    Type:  getstream.PtrTo("domain"),
})

// Create a regex filter
client.CreateBlockList(ctx, &getstream.CreateBlockListRequest{
    Name:  "phone_numbers",
    Words: []string{`\b\d{3}[-.]?\d{3}[-.]?\d{4}\b`},
    Type:  getstream.PtrTo("regex"),
})

// Create a domain allowlist (only these domains are permitted)
client.CreateBlockList(ctx, &getstream.CreateBlockListRequest{
    Name:  "trusted_domains",
    Words: []string{"myapp.com", "getstream.io"},
    Type:  getstream.PtrTo("domain_allowlist"),
})

// Create an email allowlist
client.CreateBlockList(ctx, &getstream.CreateBlockListRequest{
    Name:  "approved_emails",
    Words: []string{"support@myapp.com", "info@myapp.com"},
    Type:  getstream.PtrTo("email_allowlist"),
})

// Create a word blocklist
client.createBlockList(CreateBlockListRequest.builder()
    .name("profanity_custom")
    .words(List.of("badword1", "badword2", "offensive"))
    .type("word")
    .build()).execute();

// Create a domain blocklist
client.createBlockList(CreateBlockListRequest.builder()
    .name("blocked_domains")
    .words(List.of("spam-site.com", "phishing.net"))
    .type("domain")
    .build()).execute();

// Create a regex filter
client.createBlockList(CreateBlockListRequest.builder()
    .name("phone_numbers")
    .words(List.of("\\b\\d{3}[-.]?\\d{3}[-.]?\\d{4}\\b"))
    .type("regex")
    .build()).execute();

// Create a domain allowlist (only these domains are permitted)
client.createBlockList(CreateBlockListRequest.builder()
    .name("trusted_domains")
    .words(List.of("myapp.com", "getstream.io"))
    .type("domain_allowlist")
    .build()).execute();

// Create an email allowlist
client.createBlockList(CreateBlockListRequest.builder()
    .name("approved_emails")
    .words(List.of("support@myapp.com", "info@myapp.com"))
    .type("email_allowlist")
    .build()).execute();

// Create a word blocklist
$client->createBlockList(new CreateBlockListRequest(
    name: 'profanity_custom',
    words: ['badword1', 'badword2', 'offensive'],
    type: 'word',
));

// Create a domain blocklist
$client->createBlockList(new CreateBlockListRequest(
    name: 'blocked_domains',
    words: ['spam-site.com', 'phishing.net'],
    type: 'domain',
));

// Create a regex filter
$client->createBlockList(new CreateBlockListRequest(
    name: 'phone_numbers',
    words: ['\\b\\d{3}[-.]?\\d{3}[-.]?\\d{4}\\b'],
    type: 'regex',
));

// Create a domain allowlist (only these domains are permitted)
$client->createBlockList(new CreateBlockListRequest(
    name: 'trusted_domains',
    words: ['myapp.com', 'getstream.io'],
    type: 'domain_allowlist',
));

// Create an email allowlist
$client->createBlockList(new CreateBlockListRequest(
    name: 'approved_emails',
    words: ['support@myapp.com', 'info@myapp.com'],
    type: 'email_allowlist',
));

# Create a word blocklist
client.create_block_list(GetStream::Generated::Models::CreateBlockListRequest.new(
  name: "profanity_custom",
  words: ["badword1", "badword2", "offensive"],
  type: "word"
))

# Create a domain blocklist
client.create_block_list(GetStream::Generated::Models::CreateBlockListRequest.new(
  name: "blocked_domains",
  words: ["spam-site.com", "phishing.net"],
  type: "domain"
))

# Create a regex filter
client.create_block_list(GetStream::Generated::Models::CreateBlockListRequest.new(
  name: "phone_numbers",
  words: ['\\b\\d{3}[-.]?\\d{3}[-.]?\\d{4}\\b'],
  type: "regex"
))

# Create a domain allowlist (only these domains are permitted)
client.create_block_list(GetStream::Generated::Models::CreateBlockListRequest.new(
  name: "trusted_domains",
  words: ["myapp.com", "getstream.io"],
  type: "domain_allowlist"
))

# Create an email allowlist
client.create_block_list(GetStream::Generated::Models::CreateBlockListRequest.new(
  name: "approved_emails",
  words: ["support@myapp.com", "info@myapp.com"],
  type: "email_allowlist"
))

// Create a word blocklist
await client.CreateBlockListAsync(new CreateBlockListRequest
{
    Name = "profanity_custom",
    Words = new List<string> { "badword1", "badword2", "offensive" },
    Type = "word",
});

// Create a domain blocklist
await client.CreateBlockListAsync(new CreateBlockListRequest
{
    Name = "blocked_domains",
    Words = new List<string> { "spam-site.com", "phishing.net" },
    Type = "domain",
});

// Create a regex filter
await client.CreateBlockListAsync(new CreateBlockListRequest
{
    Name = "phone_numbers",
    Words = new List<string> { @"\b\d{3}[-.]?\d{3}[-.]?\d{4}\b" },
    Type = "regex",
});

// Create a domain allowlist (only these domains are permitted)
await client.CreateBlockListAsync(new CreateBlockListRequest
{
    Name = "trusted_domains",
    Words = new List<string> { "myapp.com", "getstream.io" },
    Type = "domain_allowlist",
});

// Create an email allowlist
await client.CreateBlockListAsync(new CreateBlockListRequest
{
    Name = "approved_emails",
    Words = new List<string> { "support@myapp.com", "info@myapp.com" },
    Type = "email_allowlist",
});

Request Parameters

key	required	type	description
name	true	string	Unique name for the blocklist (max 255 characters).
words	true	array	List of words, domains, emails, or regex patterns (max 10,000 entries).
type	false	string	Filter type: `word` (default), `domain`, `domain_allowlist`, `email`, `email_allowlist`, or `regex`.
is_leet_check_enabled	false	boolean	Detect leet speak bypass attempts (e.g., `h4ck3r` → `hacker`). Word type only.
is_plural_check_enabled	false	boolean	Detect singular/plural forms (e.g., `cat` matches `cats`). Word type only.
team	false	string	Team ID for multi-tenant blocklists.

Update a Blocklist

Replace the word list or settings of an existing blocklist.

client.update_block_list(
    name="profanity_custom",
    words=["badword1", "badword2", "offensive", "newword"],
    is_leet_check_enabled=True,
    is_plural_check_enabled=True,
)

client.UpdateBlockList(ctx, "profanity_custom", &getstream.UpdateBlockListRequest{
    Words:                []string{"badword1", "badword2", "offensive", "newword"},
    IsLeetCheckEnabled:   getstream.PtrTo(true),
    IsPluralCheckEnabled: getstream.PtrTo(true),
})

client.updateBlockList("profanity_custom", UpdateBlockListRequest.builder()
    .words(List.of("badword1", "badword2", "offensive", "newword"))
    .isLeetCheckEnabled(true)
    .isPluralCheckEnabled(true)
    .build()).execute();

client.update_block_list("profanity_custom", GetStream::Generated::Models::UpdateBlockListRequest.new(
  words: ["badword1", "badword2", "offensive", "newword"],
  is_leet_check_enabled: true,
  is_plural_check_enabled: true
))

await client.UpdateBlockListAsync("profanity_custom", new UpdateBlockListRequest
{
    Words = new List<string> { "badword1", "badword2", "offensive", "newword" },
    IsLeetCheckEnabled = true,
    IsPluralCheckEnabled = true,
});

List Blocklists

response = client.list_block_lists()

Get a Blocklist

response = client.get_block_list("profanity_custom")

Delete a Blocklist

client.delete_block_list("profanity_custom")

Attach a Blocklist to a Policy

Once created, attach your blocklist to a moderation policy to activate it. Each rule specifies the blocklist name and the action to take when matched.

await client.moderation.upsertConfig({
  key: "chat:messaging",
  block_list_config: {
    rules: [
      { name: "profanity_custom", action: "remove" },
      { name: "blocked_domains", action: "flag" },
      { name: "phone_numbers", action: "flag" },
    ],
  },
});

client.moderation().upsert_config(
    key="chat:messaging",
    block_list_config=BlockListConfig(
        rules=[
            BlockListRule(name="profanity_custom", action="remove"),
            BlockListRule(name="blocked_domains", action="flag"),
            BlockListRule(name="phone_numbers", action="flag"),
        ],
    ),
)

client.Moderation().UpsertConfig(ctx, &getstream.UpsertConfigRequest{
    Key: "chat:messaging",
    BlockListConfig: &getstream.BlockListConfig{
        Rules: []getstream.BlockListRule{
            {Name: "profanity_custom", Action: "remove"},
            {Name: "blocked_domains", Action: "flag"},
            {Name: "phone_numbers", Action: "flag"},
        },
    },
})

client.moderation().upsertConfig(UpsertConfigRequest.builder()
    .key("chat:messaging")
    .blockListConfig(BlockListConfig.builder()
        .rules(List.of(
            BlockListRule.builder().name("profanity_custom").action("remove").build(),
            BlockListRule.builder().name("blocked_domains").action("flag").build(),
            BlockListRule.builder().name("phone_numbers").action("flag").build()))
        .build())
    .build()).execute();

$client->moderation()->upsertConfig(new UpsertConfigRequest(
    key: 'chat:messaging',
    blockListConfig: new BlockListConfig(
        rules: [
            new BlockListRule(name: 'profanity_custom', action: 'remove'),
            new BlockListRule(name: 'blocked_domains', action: 'flag'),
            new BlockListRule(name: 'phone_numbers', action: 'flag'),
        ],
    ),
));

client.moderation.upsert_config(GetStream::Generated::Models::UpsertConfigRequest.new(
  key: "chat:messaging",
  block_list_config: GetStream::Generated::Models::BlockListConfig.new(
    rules: [
      GetStream::Generated::Models::BlockListRule.new(name: "profanity_custom", action: "remove"),
      GetStream::Generated::Models::BlockListRule.new(name: "blocked_domains", action: "flag"),
      GetStream::Generated::Models::BlockListRule.new(name: "phone_numbers", action: "flag"),
    ]
  )
))

await client.Moderation.UpsertConfigAsync(new UpsertConfigRequest
{
    Key = "chat:messaging",
    BlockListConfig = new BlockListConfig
    {
        Rules = new List<BlockListRule>
        {
            new() { Name = "profanity_custom", Action = "remove" },
            new() { Name = "blocked_domains", Action = "flag" },
            new() { Name = "phone_numbers", Action = "flag" },
        },
    },
});

Filter Types

Type	`type` value	Description
Word Blocklist	`word`	Exact word matching (case-insensitive). Supports leet speak and plural detection.
Domain Blocklist	`domain`	Blocks URLs by domain suffix matching. Ignores scheme and path.
Domain Allowlist	`domain_allowlist`	Only allows URLs from listed domains. Blocks everything else.
Email Blocklist	`email`	Blocks exact email addresses.
Email Allowlist	`email_allowlist`	Only allows listed email addresses. Blocks everything else.
Regex	`regex`	Pattern matching with regular expressions. Max 100 patterns per filter.

Word Matching

Word blocklists match exact words (case-insensitive). Adjacent punctuation is ignored, but partial word matches are not.

For a blocklist containing dogs, house:

"Dogs, are great" — matches (case-insensitive, ignores comma)
"I live in a lighthouse" — does not match (no partial match on house)

With leet speak detection enabled: d0g matches dog, w0m@n matches woman. With plural detection enabled: houses matches house, dog matches dogs.

Domain Matching

Domain filters match the suffix of URLs. gmail.com matches https://gmail.com, http://support.gmail.com, etc. A more specific filter like messenger.facebook.com only matches that subdomain.

Regex Matching

Regex filters support standard regular expression syntax. Tips:

Use (?i) for case-insensitive matching
Use \b for whole-word boundaries
Escape special characters with \
Max 100 patterns per filter, max 60 characters per pattern

Limits

Limit	Value
Max blocklists per app	20 (100 with multi-tenancy)
Max words per blocklist	10,000
Max regex patterns per blocklist	100
Max characters per word	40
Max characters per regex pattern	60

Rules

Multitenancy