How to Improve SMS Delivery Rates in Tanzania

To improve bulk SMS delivery in Tanzania, validate your contact list, use an approved sender, check content and credits, then investigate recipient-level delivery reports. Start with a small test across the networks your customers use. No provider can guarantee delivery to every handset, and a SENT status is not the same as DELIVERED.

Format numbers correctly

Use international format 255 followed by the nine-digit subscriber number. DARSMS also normalises supported local and +255 formats. List parsing removes duplicates and rejects invalid-format entries, but it cannot prove that a number is active, belongs to the intended customer or has consented. Check those separately.

Use an approved sender ID

Messages sent under an unregistered or misleading sender name are more likely to be blocked. Register your sender ID and keep it consistent so networks and recipients recognise you.

Watch your message content

• Avoid spam-like wording, excessive capital letters, and too many links.
• Keep URLs to a single trusted domain.
• Do not impersonate banks or government services.

Read your delivery reports

Read recipient-level reports to distinguish queued work, submitted messages and reported delivery or failure. Network reports can arrive later and may not explain every failure in detail. Review patterns before removing numbers: a temporary outage does not mean every affected contact is invalid.

What should you check when messages fail?

• One recipient: confirm the number with the customer and check whether the phone is reachable.
• One network or many numbers at once: record the time, sender and affected message IDs, then ask support to investigate.
• Queued messages: check the scheduled time, balance and any displayed processing error before sending again.
• Opted-out recipients: respect the opt-out; do not change sender names to work around it.

How do you measure delivery rate?

Use a consistent denominator and observation period. For example, 950 reported deliveries out of 1,000 submitted messages gives 95% reported delivery at the time measured. Keep rejected input and opted-out contacts separate from submitted messages. Recheck pending reports later and never interpret this rate as a read rate.