Throughput is the quiet constraint most SMS programs discover only when their Black Friday blast takes four hours to clear the queue. Plan for it before the campaign, not during.
SMS throughput is the rate at which messages can be sent, measured in messages per second (MPS). Each phone number has a throughput ceiling set by the carrier and the regulatory framework. In the US, A2P 10DLC campaigns start at 10 MPS and scale to 300 MPS or more based on brand trust score and campaign type. Toll-free numbers run at 3 MPS once verified. Hitting the ceiling queues messages, so throughput directly affects how fast a time-sensitive campaign reaches its audience.
Six things to understand about SMS throughput: what MPS is, which numbers carry which rates, how 10DLC trust scores work, how toll-free compares, how to scale, and what happens when you exceed the limit.
SMS throughput is measured in messages per second. Each phone number has a sending ceiling. A 10 MPS number can send 10 messages per second, 600 per minute, 36,000 per hour. The ceiling applies regardless of recipient (one blast of 36,000 or 36,000 individual sends both hit the same throughput wall).
In the US, A2P 10DLC campaigns start at 10 MPS by default. The brand trust score (assigned by carriers after brand verification) raises the ceiling. Top-tier brands can hit 300 MPS or more. The campaign type (marketing, 2FA, notifications) also affects the ceiling, with 2FA getting higher throughput than marketing.
Toll-free numbers (TFN) carry a 3 MPS ceiling once verified. Lower than 10DLC long codes, but TFN comes with better deliverability for transactional messaging and is often preferred for 2FA, OTP, and customer support use cases where volume is modest and reliability matters.
Non-US carriers set their own throughput rules. UK and EU typically run 10 to 30 MPS per registered sender. India requires DLT registration and has sector-specific rate limits. Any global SMS program should map throughput per market before launching. Strkr Messaging is US-focused today; international capability is unverified.
The common scaling pattern is to use multiple numbers for one campaign. Ten numbers at 10 MPS each gives you 100 MPS. Number pools (automated rotation across many numbers) are standard for high-volume marketing. Carriers monitor pool behavior for abuse, so pools must still carry proper 10DLC registration.
When you exceed throughput, messages queue inside the messaging platform. They are not dropped. A 100,000-message blast on a 10 MPS number clears in about three hours. The impact is latency: time-sensitive messages (a flash sale, an event reminder) land late and lose relevance.
US 10DLC introduced trust scores to let legitimate brands send faster than unknown ones. The score is set during brand registration and updated based on campaign behavior. Understanding how it works prevents surprise throughput caps.
When a brand registers for 10DLC, a verification process assigns a trust score (low, medium, or high). The score is based on public business records, website, EIN match, and tenure. A high trust score unlocks the top tier of throughput. A low trust score keeps the brand at the 10 MPS floor.
Each campaign in 10DLC has a declared use case: marketing, 2FA, notifications, mixed, charity, and so on. 2FA campaigns get the highest throughput ceilings (300+ MPS at top tier). Marketing campaigns get lower ceilings. Mixing use cases on one campaign tags it as marketing throughput.
High STOP rates on a campaign can lower throughput over time, even for a trusted brand. Carriers monitor opt-out rates and complaint rates. A spike signals bad list hygiene and triggers automated throughput reduction. Keep opt-out rates below 2 percent to stay in good standing.
An unverified brand or a low-trust-score brand runs at 10 MPS. For small programs (under 10,000 messages per month) this is sufficient. For high-volume marketing it is a bottleneck that forces either brand verification work or number pooling.
Verified brand with medium trust score hits the mid range. Enough throughput for most mid-market SMS programs sending 100,000 to 1 million messages per month. The mid tier is the common operating zone for B2B SaaS and mid-market retail.
Enterprise brands with high trust scores and clean campaign behavior reach the top tier. Required for mass-market consumer brands (retail, media, large event platforms) running flash campaigns to millions of subscribers. Reaching this tier takes months of clean sending behavior.
Throughput becomes real when you have a specific list and a specific delivery window. The math below is what every SMS campaign should run before scheduling the send.
Start with the list. 50,000 contacts, 500,000, 2 million. The number is the total message volume for a single-message campaign. Multi-message flows multiply the volume (a two-step opt-in campaign doubles it).
How long is acceptable for the full list to receive the message? A flash sale needs delivery in under 15 minutes. A newsletter can take hours. An event reminder scheduled a day ahead has flexible timing. The window determines the required MPS.
100,000 messages divided by 15 minutes (900 seconds) equals 111 MPS required. Divided by 60 minutes (3,600 seconds), only 28 MPS required. If current throughput is 50 MPS, the 15-minute delivery is impossible and the 60-minute delivery is comfortable.
If one number cannot clear the list in the window, add more. Ten 10DLC numbers at 10 MPS each equals 100 MPS. Pools rotate messages across numbers automatically. Each number in the pool still needs its own 10DLC registration and consent record.
TCPA restricts marketing SMS to 8am to 9pm in the recipient time zone. A 2 million-message blast cannot be sent at 3am to beat the throughput ceiling. The platform respects quiet hours automatically on scheduled sends.
During a campaign, the queue depth tells you if throughput is bottlenecking. A rising queue means messages are landing late. Alerts on queue depth let you add numbers mid-campaign or shift to a slower rollout before latency becomes a customer-visible problem.
Four patterns show up repeatedly in SMS programs that discover throughput only during the campaign. All four are avoidable with 15 minutes of planning.
A Black Friday message scheduled for 10am delivers to the last 20 percent of the list at 2pm. By then, the deal is already stale. The fix is throughput math before the send, not after.
Running marketing and 2FA on the same number pulls both into the lower throughput tier. 2FA messages queue behind marketing blasts. The fix is dedicated numbers per campaign type.
A marketing program with a 5 percent STOP rate signals bad targeting. Carriers notice and reduce throughput. Clean the list and tighten targeting before scaling the volume.
A 1-million-message blast on a 10 MPS single number takes 28 hours. Pools exist for exactly this case. Mature SMS programs set up pools before scale rather than discovering the need mid-campaign.
Strkr Messaging surfaces throughput ceilings per campaign, supports multi-number pools, and tracks queue depth in real time. SMS is 2 cents per segment, MMS is 5 cents per message, and A2P 10DLC registration is included.
SMS throughput is the rate at which messages can be sent, measured in messages per second (MPS). Each phone number has a throughput ceiling set by the carrier. In the US, A2P 10DLC campaigns start at 10 MPS and scale to 300 MPS or more based on brand trust score. Toll-free numbers run at 3 MPS once verified.
MPS stands for messages per second. It is the standard unit for SMS throughput. A 10 MPS number can send 10 messages per second, 600 per minute, 36,000 per hour. Higher-trust brands get higher MPS ceilings through the 10DLC trust-score system.
Three paths. Raise the brand trust score through 10DLC verification and clean campaign behavior. Separate campaigns by use case (2FA and notifications get higher ceilings than marketing). Use multiple numbers in a pool so throughput scales horizontally with the number count.
3 MPS once the toll-free number is verified by the carriers. Lower than long-code 10DLC throughput but with better deliverability for transactional and 2FA use cases. Toll-free verification typically takes 2 to 4 weeks and requires sample message content and opt-in disclosures.
Messages queue inside the messaging platform rather than being dropped. The delay depends on queue depth and current throughput. A 100,000-message blast on a 10 MPS number takes about three hours to clear. The real impact is latency: time-sensitive messages (flash sales, event reminders) arrive after the moment matters.
Inbound throughput is less constrained than outbound in most carrier frameworks, because recipients opting in or replying is the behavior carriers want. Platforms process inbound at much higher rates. Outbound is where the ceiling matters.
Strkr Messaging registers brands and campaigns under A2P 10DLC and surfaces per-campaign throughput in the admin console. Multi-number pools, scheduled sends, and queue monitoring are built in. SMS is 2 cents per segment and MMS is 5 cents per message.
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