Newsletter setting perMinute caps emails sent per minute

docs/configuration.md

@@ -146,6 +146,8 @@ It saves `site`, `newsletter`, `ai`, `style` and `workflow`, adds `memory` entri
 
 `senderName`, `senderEmail` and `replyTo`. `EMAIL_FROM` wins over the sender when it is set; a `postalAddress` here wins over `POSTAL_ADDRESS`.
 
+`perMinute` caps how many newsletter emails go out per minute; unset sends as fast as the provider takes them. A sender still building its reputation does better spreading a big send over half an hour or more (Gmail defers mail that arrives in a burst).
+
 ### `ai`
 
 `textModel`, `imageModel`, `videoModel` and `embeddingModel` override the variables of the same names. `knowledgeSources` are pages the AI reads besides the blog itself (an `llms.txt`, docs, a changelog feed). `voice` is the house style every draft follows.

packages/server/src/content.ts

@@ -44,6 +44,12 @@ export interface NewsletterConfig extends NewsletterSettings {
      * emails use them too (no post slug; the send id is the email's own), plus {sequence} and {step}.
      */
     emailHeaders?: Record<string, string> | null;
+    /**
+     * Most newsletter emails to send per minute (the cron runs every minute). Unset sends as fast as the
+     * provider takes them. A cap spreads a big send out, which mailbox providers prefer from a sender still
+     * building its reputation.
+     */
+    perMinute?: number | null;
 }
 
 export async function newsletterSettings(env: Env, db: D1Database): Promise<NewsletterConfig> {

packages/server/src/newsletter.ts

@@ -279,10 +279,13 @@ export async function processSends(env: Env, db: D1Database, options: AppOptions
     if (!transport) return stats;
     const deadline = Date.now() + budgetMs;
     const templates = new Map<string, NewsletterEmail>();
+    const { perMinute } = await newsletterSettings(env, db);
+    // A run handles at most the per-minute cap; the next cron run picks up the rest.
+    const cap = perMinute && perMinute > 0 ? Math.floor(perMinute) : Infinity;
 
     let leased: string | null = null;
     try {
-        while (Date.now() < deadline) {
+        while (Date.now() < deadline && stats.sent + stats.failed < cap) {
             const send = await db.prepare("SELECT * FROM sends WHERE status IN ('queued','sending') ORDER BY created_at LIMIT 1").first<any>();
             if (!send) break;
             // Claim the send for the next batch; if another worker holds it, leave it to them.
@@ -298,7 +301,7 @@ export async function processSends(env: Env, db: D1Database, options: AppOptions
                 .prepare(
                     "SELECT r.member_id, r.email, m.analytics_id FROM send_recipients r LEFT JOIN members m ON m.id = r.member_id WHERE r.send_id = ? AND r.status = 'pending' ORDER BY r.member_id LIMIT ?"
                 )
-                .bind(send.id, BATCH)
+                .bind(send.id, Math.min(BATCH, cap - stats.sent - stats.failed))
                 .all<{ member_id: string; email: string; analytics_id: string | null }>();
             if (!batch.length) {
                 await finishSend(db, send.id);