GSM 03.38, Unicode and Concatenated SMS: How to Calculate Segments Before Sending
Learn how to estimate SMS segments from the final text, encoding and concatenation method. Includes formulas, examples and controls for HTTP API and SMPP.
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Technical knowledge · A2P SMS
Routing decisions
Routing decisions
with better context.
Research and practical guidance for teams buying, selling and integrating SMS capacity.
RSS
How to Investigate DLR Discrepancies in A2P SMS Without Confusing Delivery with Human Receipt
An operational guide to correlating submissions, DLRs, and independent observations, classifying discrepancies, and escalating incidents with reproducible evidence—without presenting DELIVRD as proof that a message was read.
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How to Design Idempotent Retries in an SMS API to Avoid Duplicate Sends
An operational guide to handling timeouts and ambiguous SMS outcomes without turning a technical retry into a second message. Includes idempotency keys, persistent states, reconciliation through callbacks or DLRs, and OTP-specific controls.
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