Recovery Week After a Fail-Rate Spike

Recovery Week After a Fail-Rate Spike.

Analyzing the DLR Spike

When a deliverability spike occurs, the first action is a deep dive into webhook logs. We look for specific error codes returned via the IOSOR API. If the DLR status shows a high volume of undelivered OTP messages, we verify the E.164 formatting and the destination prefix. High fail rates often stem from aggressive filtering or incorrect routing logic. By auditing the last 24 hours of SMS traffic, we identify if the spike was localized to a specific region or a broad failure. This post-mortem phase is critical to ensure that the recovery week starts with a clean slate and a clear understanding of the failure.

Implementing Hard Traffic Caps

To prevent further reputation damage, we implement hard caps on all active sub-accounts. During the recovery week, traffic should be throttled to 10% of the normal volume. This allows the system to process SMS queues without overwhelming the downstream infrastructure. Using the IOSOR console, we set per-second and per-minute limits. If a webhook reports a «STOP OK» response from a handset, we immediately blacklist that destination to maintain a healthy sender profile. Throttling is not just about volume; it is about pacing the delivery to ensure high DLR success during the stabilization phase.

Smoke Testing with JIT Numbers

Recovery requires a fresh start for number resources. We utilize JIT (Just-In-Time) provisioning to assign new numbers for smoke testing. Instead of relying on old, potentially flagged assets, we initiate a prepaid hold for a small batch of numbers. These are assigned to the most critical OTP flows. We send test messages to a controlled group of handsets to verify that the path is clear. This JIT approach ensures that we are not wasting MRC (Monthly Recurring Charges) on numbers that might be blocked. Each assigned number is monitored for its individual DLR performance before we scale the traffic.

Financial Thresholds and Scaling

The IOSOR ledger requires a USD 20 prepaid floor to keep the account active. During the recovery week, we monitor the balance closely to avoid service interruptions. As traffic begins to normalize and DLR rates climb back to acceptable levels, we prepare for the soft review that occurs near the USD 1,000/month spend mark. This review is a manual check of traffic quality and compliance. By maintaining a clean ledger and consistent payment history, we ensure that the account remains in good standing. Scaling should be incremental, increasing volume by 20% every 48 hours if performance holds.

Recovery Resources

To further optimize your recovery strategy, consult the following technical guides. These playbooks provide additional context on maintaining high deliverability and preparing for large-scale launches within the IOSOR ecosystem:

• OTP launch week: prepaid checklist that prevents burn
• SMS low-deliverability playbook
• traffic_ok gate before pilot volume

Start with IOSOR

Open the IOSOR console immediately to set hard traffic caps at 10% of normal baseline volume across all active sub-accounts. Audit your latest webhook payload logs to isolate failing destination prefixes and DLR status codes. Provision a small batch of JIT numbers to run controlled smoke tests before unlocking higher traffic gates.

IOSOR takeaway

Successfully recovering from a deliverability spike requires immediate traffic throttling, diagnostic log audits, and controlled asset isolation. Pushing full volume through compromised routes or flagged sender pools permanently degrades carrier reputation and creates prolonged delivery failures.

Do throttle volume to a strict 10% baseline immediately via the IOSOR API while running JIT smoke tests on fresh sender resources. Don't blast full traffic through flagged routes or ignore early webhook DLR anomalies, as unaddressed fail spikes trigger permanent carrier blocks.