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How to send High-Volume Outbound Messages

Raquel Updated by Raquel

If you need to send messages to tens of thousands — or millions — of contacts, this guide walks you through the recommended approach on Turn: using Reminders (not the API) to build your Meta messaging tier and scale safely.

1. Why Reminders, not the API

  • The Turn API is rate-limited to 60 messages/second for external callers — that limit does not apply to Reminders, which is an internal process Turn controls.
  • Reminders is purpose-built for bulk messaging: it automatically schedules up to 80% of your current tier to avoid triggering Meta's blocking behaviour and to protect your quality rating.
  • Using the API directly requires you to handle all edge cases (retries, delivery receipts, throttling) yourself; Reminders handles these for you.

2. Understanding Meta's messaging tiers

  • Meta enforces tiers: 1K → 10K → 100K → unlimited contacts/day.
  • Tier growth is governed by quality rating (how recipients respond). High engagement → faster growth. Blocking or marking as spam slows or reverses growth.
  • Turn has no control over how fast Meta upgrades your tier, but Reminders is designed to maximise your speed of progression by never exceeding the current tier limit.

3. Preparing your contact list (CSV upload)

  • Add custom profile fields that will help work as segment identifier (e.g. village/region code/group), then download the Template Helper on People > Import
  • You can upload in batches. Turn de-duplicates on phone number, so re-uploading contacts is safe.
  • For very large files (2M+) expect ingestion to take a couple of hours.

4. Staged rollout strategy

Start with 10,000 contacts to begin building your tier before uploading your full database. Once that first batch is sent and your tier grows, continue uploading the remainder. Reminders will automatically start consuming each new tier level as it becomes available.

5. Dynamic content delivery using the Apps feature

For use cases where different contacts should receive different media or templates (e.g. region-specific weather forecasts):

  1. Prepare a weekly CSV mapping segment codes → media asset identifiers + template names (usually a few hundred rows, not millions).
  2. Host that CSV at an HTTP endpoint Turn can fetch, or supply it manually each cycle.
  3. Use a Turn App to: ingest the values at send time → look up the correct media asset and template, for example → output those values back to the journey.
  4. Your reminder triggers a journey that uses the App output to send the right template to each contact.

This avoids pre-creating one reminder per segment — the App handles the routing logic at runtime.

6. Handling replies: set up an auto-reply

When sending to large audiences, some contacts will reply. Recommended:

  • Create a simple Catch-All trigger journey that auto-acknowledges the message ("Thanks for your message — we'll get back to you soon").
Positive engagement from auto-replies contributes to your quality rating.

7. Analytics and reporting: BigQuery integration

For delivery tracking and dashboard creation:

  • Turn's BigQuery integration streams a live replica of all sent/received messages with a ~15-minute refresh.
  • Host BigQuery in the same region as your contacts (e.g. Mumbai for India) for data sovereignty.
  • Connect to Looker Studio / any BI tool for dashboards.

WhatsApp policy requires that contacts have explicitly consented to receive messages from your organisation before you message them. Before sending:

  • Confirm how consent was captured (e.g. government enrolment form, opt-in flow).
  • Add an opt-out option in your messaging flow (e.g. "Reply STOP to unsubscribe").
  • Consider an explicit opt-in message as the first touchpoint if consent is uncertain.
Failure to meet consent requirements can result in high block rates, which damages your quality rating and tier.

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