A field guide to how throughput, brand hierarchy, and ramp-up work across 10DLC, toll-free, and short codes. The standard Volt sender reference.
On 10DLC, sending capacity is set at the brand level by The Campaign Registry, not at the campaign or number level. Everything traces back to the EIN. A single sender can register multiple EINs, each with one or more brands, and each brand can run one or more campaigns. The structure below is illustrative: two EINs, three brands, four campaigns, all three number types in play.
Each channel has a different upper ceiling. Across the board, Volt's recommendation is to operate at roughly the midpoint of each ceiling as the safest sustained sending volume. Pushing closer to the maximum increases the risk of carrier blocks and aggregator filtering.
Inside the 10DLC channel, each US carrier enforces throughput differently. These limits feed into the 50,000/day safe target shown above. T-Mobile is usually the binding constraint at the brand level; AT&T and Verizon limits matter at the per-number level for burst behavior.
All three channels follow the same warm-up shape. Start small, increase steadily, give carriers two weeks to see consistent, predictable behavior before settling at the daily target. Only the target ceiling changes by channel. The schedule below assumes a clean signal: opt-out and negative response patterns gate every step up.
Start at 5,000 / day across the brand. Add roughly 5K each day through week one, then taper increases in week two. Settle at 50,000 / day per brand by Day 14. Doubling daily is acceptable, but not required.
Start at 10,000 / day. Increase by roughly 10K daily in week one, then ease into week two. Settle at 100,000 / day per TFN. Grow TPM alongside daily volume from 30 TPM up to your operational rate.
Start at 25,000 / day. Add roughly 25K daily in week one, with smaller steps in week two. Settle at 250,000 / day per code. Stick to a single content type during the warm-up window before diversifying.
The schedule above assumes a happy path. If opt-out rate or negative responses climb during the ramp, you do not keep scaling. You pause, diagnose, and fix the underlying issue before stepping up again. The goal is to catch problems at lower volumes, because the same issues only get worse at scale.
Negative response rate is a parallel signal. A surge in negative replies (frustration, confusion, complaints) is an early warning even when opt-outs look fine. We do not have a hard quantitative threshold yet, but a noticeable spike is reason enough to pause and diagnose. Treat it the same way as the opt-out signal: stop scaling, fix the issue, then resume.
Once you are at full capacity, the goal is to stay there. Carriers and aggregators can throttle, filter, or block any sender whose behavior drifts from its registration. These patterns consistently keep accounts healthy across all three channels.
Sent messages do not need to be identical to your registration samples, but should stay close in structure and intent. Drift is the most common cause of Verizon filtering, TFN aggregator blocks, and short code review flags.
Every campaign-initiated message must include opt-out language such as "Reply STOP to unsubscribe." Enforced at the carrier level across all three channels.
Identical messages sent to large blocks at the same minute is a spam signature. On AT&T, sustained per-second bursts trigger 30-minute blocks even when you are well under your total daily cap. Spread sends across the day.
Watch delivery rate by carrier. T-Mobile dipping usually means brand cap. AT&T dipping usually means a TPM issue. Verizon dipping usually means content drift. The signal tells you what to fix.
Zipwhip's bot-driven filtering is highly sensitive to opt-out rate. Spread your daily volume across several hours rather than batching, and act on opt-outs immediately. Anything above 1% should trigger a hold on volume increases.
Any future jump above 1.5x your established daily average should ramp again over several days. Holiday campaigns, new vertical launches, and acquired list activations all qualify, on every channel.
During the first two weeks on a new short code, send a single content type per code. Carriers want to see predictable behavior before they trust diversified content. After the warm-up window, diversify.
Avoid sending identical copy across multiple brands or campaigns. Carriers and aggregators flag repeated identical content as a spam signature, even when it is sent from different numbers. Keep copy structurally similar where useful, but vary the actual language.
Using the same link shortener domain across multiple brands increases the risk of all of them getting blocked together. If one brand traffic gets flagged, every brand sharing that shortener inherits the reputation hit. Use brand-specific shorteners or verified domains.