You registered one brand. You registered one campaign. You're sending one blast to one list. So why does the delivery log show AT&T numbers clearing in seconds while a big chunk of your T-Mobile numbers sit in a queue for an hour, then trickle out?
This confuses a lot of high-volume senders, and it's not a bug in your platform. "10DLC" is a single registration standard, but the throughput and filtering rules behind it are set per carrier, independently, using different math. Your campaign doesn't have one speed limit. It has one for AT&T, one for T-Mobile, one for Verizon, and each is governed by its own trust logic.
Full disclosure: I work for ReadySMS, and we handle 10DLC registration in-app. That means I stare at these uneven delivery patterns all day. Here's what's actually happening under the hood, and what you can do about it.
One registration, several independent speed limits
When your campaign gets approved through The Campaign Registry (TCR), that approval propagates to each carrier. But each carrier then applies its own throughput assignment based on its own view of your brand's trust.
- AT&T assigns throughput in messages-per-minute (MPM) tiers tied to your brand's trust score. Higher score, higher tier, more messages per minute.
- T-Mobile doesn't think in per-minute rates the same way. It assigns a daily message cap (a "brand tier") — a hard ceiling on how many messages your brand can send across all your campaigns to T-Mobile subscribers in a 24-hour window.
- Verizon runs its own per-second and filtering logic on top.
So "my campaign is approved" tells you almost nothing about how fast it'll actually move on any given network. The registration is the entry ticket. The throughput assignment is a separate, per-carrier decision — and that's where the unevenness comes from.
If the whole idea of a per-second sending ceiling is new to you, we broke down the TPS math separately — that piece explains why a 50,000-contact blast can take hours even on a healthy campaign.
The trust score you don't see
Both carriers lean on a brand trust score — a number computed from your registration data, your EIN verification, whether you opted into external vetting, and (over time) your actual sending behavior. You don't get a clean dashboard number for it, but it's the lever that moves everything.
Two brands can register the identical campaign use case and land in completely different tiers because one submitted a clean EIN with a matching legal name and a real website, and the other submitted a sole-prop with mismatched details. TCR flags the mismatch, the brand's trust score drops, and every carrier reads that lower score differently.
Here's the asymmetry that trips people up: AT&T tends to be more forgiving on the low end, T-Mobile more punishing. A middling trust score might still clear AT&T at a reasonable MPM tier, while T-Mobile drops you into a low daily cap. Same brand. Same score. Different consequence. That's why your log shows AT&T flying and T-Mobile crawling.
A worked example of the T-Mobile daily cap
Say you're on a low T-Mobile brand tier with a daily cap of, roughly, a few thousand messages across your brand. (T-Mobile's exact tier numbers shift, so treat this as illustrative, not a quote.) You've got a 40,000-contact list, and historically about 30–40% of US mobile numbers are on T-Mobile's network including its MVNO brands like Metro and Mint.
That's ~14,000 messages that need to reach T-Mobile subscribers. If your daily cap sits at a few thousand, the platform can't push them all through today. It queues the overflow and releases it as your window resets. Meanwhile the AT&T portion — also ~14,000 or so — clears in a fraction of the time because AT&T's per-minute tier lets it flow.
From your seat it looks like "half my list is stuck." What's actually happening is one carrier is metering you at the brand level and the platform is correctly holding messages rather than getting them filtered or hard-blocked.
Why a well-behaved platform queues instead of blasting
There's a temptation to want your provider to "just send faster." Don't. If a platform ignores the carrier-assigned ceiling and floods, three things happen, all bad:
- Messages over the limit get filtered — dropped silently, often marked as delivered in a way that lies to you. (We wrote about the gap between a "delivered" receipt and what the carrier actually confirmed.)
- Your trust score degrades, which lowers your future ceiling — you get slower tomorrow for going too fast today.
- Repeated violations can get a campaign flagged or a number reputation-poisoned.
Queuing to the carrier's assigned rate is the correct behavior. It feels slow, but it protects your deliverability and your trust score. The fix isn't a faster platform — it's a higher ceiling.
How to actually raise the T-Mobile ceiling
You raise per-carrier throughput by raising your brand trust score. Concretely:
1. Get your registration data pristine
The single biggest, free lever. Your legal business name, EIN, and address on the 10DLC brand must match your IRS records exactly. A mismatch caps your score before you've sent a single text. If your campaign got rejected or downgraded for vague reasons, our rejection-decode walkthrough covers the fields that matter most.
2. Make sure your campaign use case is honest
Registering a "Marketing" campaign when you're sending transactional order updates — or vice versa — creates a mismatch carriers penalize. We covered exactly how this silently drops delivery here. Match the use case to the actual traffic.
3. Consider external brand vetting
This is the direct dial on the trust score. Standard vetting runs $40 one-time, Enhanced runs $100 one-time, and a passing score bumps your assigned tiers — often most visibly on the T-Mobile side, because that's usually where a low tier is throttling you.
Whether it's worth it depends entirely on volume. If you're sending a few thousand a month, standard 10DLC (~$10/mo brand + ~$20/mo campaign) is plenty and vetting buys you throughput you'll never use. If you're routinely hitting a daily cap and watching T-Mobile messages queue, $40 to lift the ceiling pays for itself in one send. We ran the full break-even math on brand vetting here.
A quick reference for what governs what
| Factor | AT&T | T-Mobile | What raises it |
|---|---|---|---|
| Throughput model | Messages-per-minute tier | Daily message cap (brand tier) | Trust score |
| Sensitivity to low trust | More forgiving | Harsher — low tier = tight daily cap | Clean registration |
| Biggest free lever | Matching EIN/legal name | Matching EIN/legal name | Data accuracy |
| Paid lever | External vetting | External vetting (often bigger effect) | $40 / $100 one-time |
| What happens if you exceed | Filtered / dropped | Queued, then filtered | Send within assigned rate |
The pattern to internalize: AT&T meters your pace, T-Mobile meters your daily volume, and both read the same trust score to decide how generous to be.
Where ReadySMS fits
We register your brand and campaign in-app, and most approvals land same-day to a few days. When your traffic hits a carrier's assigned rate, the platform queues to that rate rather than flooding and getting you filtered — so your "delivered" numbers stay honest. If you're a GoHighLevel shop, the native GHL integration keeps all of this mapped per sub-account so one client's low tier doesn't drag down another.
When you outgrow standard 10DLC and the T-Mobile cap becomes your bottleneck, you can add brand vetting from the same place you registered — no re-onboarding, no porting. And if you're consistently sending past 50,000 segments a month, the Growth rate ($0.016/segment) kicks in automatically, which is roughly when vetting-level throughput starts mattering anyway.
The practical takeaway
If your delivery log looks lopsided — AT&T fast, T-Mobile slow — you're not broken and your platform isn't misconfigured. You're seeing two carriers apply two different throughput models to one trust score, and T-Mobile's daily-cap model is stricter on the low end.
The move, in order: fix your registration data so it matches your IRS records exactly, confirm your campaign use case matches your real traffic, and then — only if volume justifies it — pay for external vetting to lift the ceiling T-Mobile is actually enforcing.
If you want to see where your current numbers land, the cost calculator will show you segment math for a full blast, and you can register a brand with 2,500 free credits to test delivery on your own list before committing to anything. Start there, watch the per-carrier split in your logs, and only reach for vetting once T-Mobile is clearly the thing holding you back.