Allowlists and Blocklists for Agent Mailboxes Nylas introduced typed lists for Agent Mailboxes, allowing support staff to update blocklists and allowlists via a single POST request without redeploying configuration. Lists validate values on write, preventing common errors like pasting email addresses into domain lists, and changes take effect immediately across all referencing rules. Before: blocking a new spam domain meant editing a rule definition, reviewing the change, and redeploying config. After: it's one POST that appends a string to a list, and every rule referencing that list picks up the new value immediately — no rule edits, no deploy, and a support person can do it from a script. That's the design idea behind Lists on Nylas Agent Accounts currently in beta, along with the Policies and Rules they work with : separate the values from the logic . Rules describe what to do; lists hold the ever-changing who. A list is a typed collection, and the type is fixed at creation — immutable afterward: | Type | Holds | Matches against | |---|---|---| domain | Domain names example.com | from.domain , recipient.domain | tld | Top-level domains com , xyz | from.tld , recipient.tld | address | Full addresses user@example.com | from.address , recipient.address | The typing isn't cosmetic. Values are validated on write — a domain list rejects a full email address — which catches the classic operational error of pasting alice@example.com into a domain blocklist and silently matching nothing. Values are also lowercased and trimmed on write, and duplicate additions are silently ignored, so your sync script doesn't need its own normalization or dedupe pass. Create the list, fill it, reference it from a rule via the in list operator: 1. Create curl --request POST \ --url "https://api.us.nylas.com/v3/lists" \ --header "Authorization: Bearer