A six-message two-way SMS exchange on a registered US 10DLC long code costs US$0.0618 to US$0.0723 in message plus carrier fees, depending on the recipient’s network. On top sit a one-time brand fee of US$4.50 to US$46, a US$15 campaign vetting fee, US$1.50 to US$10 per campaign per month, and US$1.15 a month for the number. All figures read at source on 10 September 2026.
Every A2P 10DLC pricing guide we could find prices a blast: one message out, per recipient, done. An AI SMS agent does not blast. It opens, it waits, the person replies, it replies back. In a balanced exchange, half the segments crossing the wire are travelling towards you, and inbound segments are billed. This page prices the conversation instead of the send, using Twilio’s own published tables, AWS End User Messaging’s own published fee list, and The Campaign Registry’s own statements, each linked and dated below.
How much does A2P 10DLC cost per month?
There are two separate cost layers and operators routinely budget only for the second. The registration layer is charged by the carriers and The Campaign Registry and passed through by your provider; the per-segment layer is charged every time a message moves.
The table below is Twilio’s registration fee schedule, taken from Twilio’s Pricing and Fees for A2P 10DLC Service article (last updated 15 June 2026, read 10 September 2026).
| Fee | Amount (USD) | When it is charged |
|---|---|---|
| Sole Proprietor brand registration | US$4.50 | One-time, at creation with TCR |
| Low Volume Standard brand registration | US$4.50 | One-time, no Secondary Vetting |
| Standard brand registration | US$46 | One-time, includes Secondary Vetting |
| Campaign use case registration | US$15 vetting fee | One-time, per campaign |
| Sole Prop (Starter) campaign | US$2/month | At approval, then monthly until deactivated |
| Standard campaign | US$10/month | At approval, then monthly until deactivated |
| Low-volume mixed use case | US$1.50/month | At approval, then monthly until deactivated |
| Charity / 501(c)(3) nonprofit | US$3/month | At approval, then monthly until deactivated |
| Emergency Services | US$5/month | At approval, then monthly until deactivated |
| Authentication Plus retry | US$12.50 per retry | Public, for-profit brands only |
Two details in that article are worth reading twice. The brand fee is charged at creation, so a brand that lands in an unverified state has already cost you the money. And the monthly campaign fee is billed “at time of approval, then as a renewal fee for the same amount each month, unless the Campaign is deactivated/deleted” — a campaign you stopped using but never deleted is still billing.
These are 2025-08-01 numbers. Twilio’s article records the increases TCR applied on that date: brand registration US$4.00 to US$4.50, standard vetting US$40.00 to US$41.50, vetting appeal US$10.00 to US$11.00, and Authentication Plus from US$0.00 to US$12.50 per retry for eligible brands. Any guide still quoting US$4 and US$44 is quoting the pre-August-2025 schedule.
Do I get charged for inbound SMS replies?
Yes, twice over, and this is the single largest gap between a blast budget and an agent budget.
First, your provider bills the inbound segment. Twilio’s US SMS pricing page (read 10 September 2026) prices long code SMS at US$0.0083 outbound and US$0.0083 inbound — identical. A reply costs exactly what a send costs before carriers are counted at all.
Second, several carriers add an inbound pass-through fee. The long code carrier fee table on that same page reads:
| Carrier | SMS outbound | SMS inbound | MMS outbound | MMS inbound |
|---|---|---|---|---|
| AT&T | US$0.0035 | US$0.0035 | US$0.009 | US$0.009 |
| T-Mobile | US$0.0045 | US$0.0025 | US$0.01 | US$0.01 |
| Verizon | US$0.0045 | no fee listed | US$0.007 | no fee listed |
| US Cellular | US$0.005 | US$0.0025 | US$0.01 | US$0.01 |
| All other carriers | US$0.004 | no fee listed | US$0.01 | no fee listed |
Read that table by column, not by row. It has five columns, and the two MMS columns are the ones most often collapsed into the SMS columns by summarisers and by people skim-reading a five-wide grid. Verizon’s US$0.007 is its MMS outbound long code fee. Verizon’s SMS inbound cell is blank. We flag this because a search summariser gave us a flat “US$0.003 per segment” for Verizon on the same day, and a second reading of the same page produced “US$0.007 inbound” — both wrong against the table itself. Open the page and count the columns.
There is also a live inconsistency inside Twilio’s own documentation, and you should know which page governs your bill. The fees article states: “In general, the fees are applied for each outbound SMS segment or MMS message. T-Mobile (including Sprint) also applies fees to inbound SMS and MMS.” Its prose names only T-Mobile. The pricing table it points you to for “complete details” lists inbound SMS fees for AT&T (US$0.0035) and US Cellular (US$0.0025) as well. Both pages were read on 10 September 2026. The table is the more specific and the more recently maintained artefact, and it is the one the fees article defers to, so it is the one we have costed from.
One piece of good news, verified rather than assumed: inbound does not eat your T-Mobile daily cap. Twilio’s T-Mobile daily message limits article (last updated 18 June 2026) says the limit “is based on the total number of outbound SMS segments and MMS messages sent to T-Mobile (including Sprint and MetroPCS)”, and the limit table is headed “T-Mobile message limit (SMS segments + MMS) outbound”. Inbound costs you money; it does not cost you headroom.
What does one two-way conversation actually cost?
Here is the worked calculation, which we call the two-way segment ledger. Inputs: one conversation of six single-segment GSM-7 messages — three sent by the agent, three sent by the human — on a registered 10DLC long code, at Twilio list price with no volume discount applied. Substitute your own message count and your own provider’s per-segment rate; the shape does not change.
| Carrier | 3 outbound segments | 3 inbound segments | Total per conversation | Inbound share |
|---|---|---|---|---|
| AT&T | US$0.0354 | US$0.0354 | US$0.0708 | 50.0% |
| T-Mobile | US$0.0384 | US$0.0324 | US$0.0708 | 45.8% |
| US Cellular | US$0.0399 | US$0.0324 | US$0.0723 | 44.8% |
| Verizon | US$0.0384 | US$0.0249 | US$0.0633 | 39.3% |
| All other carriers | US$0.0369 | US$0.0249 | US$0.0618 | 40.3% |
Each outbound cell is 3 x (US$0.0083 + that carrier’s outbound fee). Each inbound cell is 3 x (US$0.0083 + that carrier’s inbound fee, or US$0.0083 alone where no inbound fee is listed). The AT&T row is the one to memorise: an inbound segment on AT&T costs US$0.0118, exactly the same as an outbound one.
That gives us the rule this page exists to state. The inbound-half rule: on a US 10DLC long code, between 39% and 50% of the message cost of a balanced two-way conversation is the half you did not send. A budget built from outbound segments alone understates a conversational agent by that much, before a single registration fee is counted.
What does a month of 5,000 contacts cost end to end?
Same ledger, scaled. Inputs you can change: 5,000 contacts messaged once, a 20% reply rate, and each replying conversation adding three inbound plus three further outbound segments. That is 8,000 outbound and 3,000 inbound segments, 11,000 in total. The 20% is an arithmetic input we chose so the sum is checkable, not a benchmark we are claiming; put your own reply rate in.
Twilio base cost is identical across every row: 11,000 x US$0.0083 = US$91.30. Only the carrier layer moves. Each row below shows the bill if the whole list sat on that one network, which brackets your real blended number.
| If the whole list were on | Carrier fees | Messages total | Plus campaign and number | First month, with registration |
|---|---|---|---|---|
| AT&T | US$38.50 | US$129.80 | US$140.95 | US$201.95 |
| T-Mobile | US$43.50 | US$134.80 | US$145.95 | US$206.95 |
| US Cellular | US$47.50 | US$138.80 | US$149.95 | US$210.95 |
| Verizon | US$36.00 | US$127.30 | US$138.45 | US$199.45 |
| All other carriers | US$32.00 | US$123.30 | US$134.45 | US$195.45 |
The fixed additions are a US$10 Standard campaign per month and a US$1.15 long code per month; the first-month column adds the US$46 Standard brand fee and the US$15 campaign vetting fee once. Steady state, that is US$0.027 to US$0.030 per contact touched, or about US$0.13 to US$0.15 per conversation that actually happened.
Now the comparison that matters. Price the same month the way a one-way guide prices it — 8,000 outbound segments and nothing else — and you get US$94.40 to US$106.40. The two-way number is 24% to 38% higher on identical traffic. The gap is not a rounding error; it is the reply.
Which brand and campaign tier should I register?
For a conversational agent, the tier decision is a throughput decision long before it is a fee decision. One message per second sounds adequate until forty people reply to the same send at once and your agent has to answer all of them at one segment per second. The thresholds below come from Twilio’s comparison of Sole Proprietor, Low Volume Standard and Standard registration (last updated 12 September 2025) and Twilio’s message throughput and Trust Scores article (last updated 9 September 2026), both read 10 September 2026.
| Tier | Monthly campaign fee | Daily segment ceiling | Throughput | Numbers per campaign | Choose it when |
|---|---|---|---|---|---|
| Sole Proprietor | US$2 | Up to 3,000/day to US, hard limit 1,000/day to T-Mobile | 1 MPS | 1 | No EIN. Customers with an EIN are not eligible. |
| Low Volume Standard | US$1.50 (low-volume mixed) | Up to 6,000/day to US, hard limit 2,000/day to T-Mobile | 3.75 MPS toward major US networks | More than 1 | You have an EIN and stay under 6,000 segments a day. |
| Standard | US$10 | Up to 200,000/day to T-Mobile, by Trust Score | Up to 225 MPS by Trust Score | More than 1 | Above 6,000 a day, or you need real burst capacity. |
The T-Mobile cap is stricter than that summary implies, and it is worth knowing before you register. Per the T-Mobile daily limits article, the cap is applied at EIN level and shared across every brand and platform registered under that EIN: Trust Score 75-100 gets 200,000 segments a day, 50-74 gets 40,000, 25-49 gets 10,000, and 1-24 gets 2,000. Sole Proprietor brands are capped at 1,000 segments a day. A Low Volume Standard brand that is not a Russell 3000 company gets 2,000. Exceed it and messages fail with error 30023 until midnight Pacific.
The trap for an agency or a platform is the shared-EIN clause. Twilio’s example is explicit: a company registered on its own Twilio account and again through a third-party tool shares one brand-level limit across both. Two registrations do not buy two ceilings.
Note also that the comparison article was last updated on 12 September 2025 and still shows the pre-increase US$4 and US$44 brand fees, while the pricing article shows US$4.50 and US$46. Where two pages from the same vendor disagree, take the one that is dated later and is specifically about fees.
Is registration cheaper through Twilio or AWS End User Messaging?
The registration fees are carrier and TCR pass-throughs, so the interesting question is not who is cheaper but who itemises. AWS End User Messaging’s pricing page (read 10 September 2026) publishes its 10DLC fees as a list rather than a table.
| Item | Twilio (fees article, 15 June 2026) | AWS End User Messaging (pricing page, read 10 Sept 2026) |
|---|---|---|
| Company / brand registration | US$4.50 Sole Prop or Low Volume Standard; US$46 Standard, includes Secondary Vetting | US$4.50 one-time per company; US$4.50 again on resubmission |
| Vetting | Bundled into the US$46 Standard fee | US$41.50 one-time per vetting request |
| Authentication Plus | US$12.50 per retry, public for-profit brands | US$12.50 one-time per company, public profit brands; US$12.50 again on resubmission |
| Campaign registration | US$15 vetting fee | US$50 activation fee required by T-Mobile, which AWS states “will be postponed until further notice” |
| Campaign monthly | US$1.50 to US$10 by use case | US$10 regular, US$2 low-volume |
| Number monthly | US$1.15 long code | US$1 per 10DLC number |
Do the arithmetic on the top two rows and the pass-through becomes visible: AWS’s US$4.50 registration plus its US$41.50 vetting fee is US$46.00, which is exactly Twilio’s Standard brand fee, described by Twilio as including Secondary Vetting. Same two charges from the same registry, presented as one line or as two. That is what “pass-through, no added cost” looks like when you can see both invoices.
Two honest limits on this comparison. AWS’s per-message SMS prices sit behind a JavaScript pricing tool and a downloadable CSV rather than in the page HTML, so we have not read them and this table covers registration and recurring fees only. And the US$50 campaign activation fee AWS lists, which it attributes to T-Mobile, is currently postponed, so it is a stated future liability rather than a charge you will see this month.
What costs are not on the price page?
These are the line items that turn a modelled budget into an actual invoice.
- Failed messages still cost. Twilio’s US SMS pricing page carries a footnote setting a failed message processing fee of US$0.001 per message, applied only to messages that terminate in a Failed status. Small per unit, real at list-scrubbing volumes.
- Waiting is a cost. Twilio’s throughput article, last updated 9 September 2026, carried a banner saying campaign reviews are currently taking 5 to 10 days. The T-Mobile limits article, last updated 18 June 2026, carried a banner saying 10 to 15 days on the same day we read both. Budget for the longer figure and treat the shorter one as the optimistic case.
- Every STOP is a billed inbound segment. Opt-outs arrive as inbound messages on the same meter as a warm reply. That is a strong argument for handling them properly rather than cheaply; we have written separately on what an AI agent should do when someone opts out mid-conversation.
- Toll-free skips 10DLC campaign registration but not verification, and verification has a deadline five days out. If you are considering a toll-free number instead, Twilio’s Toll-Free Verification Onboarding Guide (last updated 17 June 2026, read 10 September 2026) states: “Starting September 15, 2026, toll-free verification submissions must include separate URL fields for your Privacy Policy and Terms and Conditions. Submissions missing these links will be rejected with error 30493. This applies to new submissions only; existing verifications do not need updates.” Toll-free SMS is not subject to the 10DLC campaign registration requirements, per Twilio’s throughput article, but it is subject to this. If you have a submission drafted, add the two URLs before 15 September 2026.
- A rejected campaign is dead spend plus dead time. The brand fee is charged at creation regardless of outcome. Our companion piece on why A2P 10DLC campaigns get rejected for AI SMS agents, and the exact fixes covers the reasons and the appeal path; this page deliberately stays on the fees.
When does the per-segment price stop being the number that matters?
Run the ledger honestly and one thing becomes obvious: at 5,000 contacts a month the carrier bill is under US$150. Nobody’s business case turns on US$150. What the ledger is genuinely useful for is spotting the points where the economics change shape.
| Situation | What the arithmetic says | What to do |
|---|---|---|
| Under about 1,000 segments a day | Sole Proprietor or Low Volume Standard covers you at US$1.50 to US$2 a month | Register the cheap tier and stop optimising. The fee layer is noise. |
| Reply rates rising, or longer exchanges | Your blended bill moves toward the 39% to 50% inbound band, and your 1 or 3.75 MPS ceiling becomes the binding constraint | Move to a Standard brand for throughput, not for price. |
| Above 6,000 segments a day, or several client brands | Shared EIN caps and per-campaign monthly fees start compounding | Model per EIN, not per campaign, before you sell the capacity. |
| Conversation quality is the constraint, not volume | The whole fee stack moves by a few dollars a month; the reply rate moves the result | Spend the attention on what the agent says, not on shaving US$0.0005 a segment. |
That last row is the honest conclusion of a cost page. Carrier economics decide whether you can afford to run a two-way agent at all; they never decide whether it works. What decides that is whether the reply gets a good answer fast, which is a platform and orchestration problem — the same problem we describe in why an AI voice agent bill comes in higher than minutes times rate, and the reason follow-up sequencing is worth designing properly rather than guessing, as covered in AI follow-up pacing across channels.
Zian AI builds autonomous AI sales agents that run phone, SMS, email and WhatsApp outreach, through SmartReach AI™, which orchestrates message, channel and timing by country, industry and profile, and PrecisionPitch AI™, which split-tests scripts against real success outcomes. Zian is in partnership-application beta: there is no free trial and no self-serve signup, so if the fee stack above is the part you were hoping to hand over, that hand-over starts with a conversation, not a credit card. Apply For Partnership.
Frequently asked questions
Do I pay for inbound SMS on A2P 10DLC?
Yes. Twilio prices long code SMS at US$0.0083 per segment in both directions, and the carrier fee table adds inbound fees of US$0.0035 on AT&T and US$0.0025 on T-Mobile and US Cellular. Verizon and the other carriers list no inbound SMS fee. Read 10 September 2026.
How much does a two-way SMS conversation cost in the US?
A six-segment exchange, three out and three in, costs US$0.0618 to US$0.0723 depending on the network, at Twilio list pricing with no volume discount. Between 39% and 50% of that total is the inbound half.
Who actually charges the A2P 10DLC registration fees?
The carriers and The Campaign Registry, passed through by your provider. TCR is the record rather than the referee: its Resources FAQ states that The Campaign Registry does not review, approve, or reject campaigns, and that this is solely done by the CSPs and their upstream connection partners. Twilio states it passes both registration and carrier fees through with no added cost.
Does inbound SMS count towards my T-Mobile daily limit?
No. Twilio documents the T-Mobile cap as based on the total number of outbound SMS segments and MMS messages sent to T-Mobile, including Sprint and MetroPCS, and its limit table is headed as outbound. Inbound segments cost money but do not consume the daily allowance.
What is the cheapest A2P 10DLC setup for a low volume AI agent?
A Low Volume Standard brand at US$4.50 one-time with a low-volume mixed campaign at US$1.50 a month, plus the US$15 campaign vetting fee and US$1.15 a month for a long code. The ceiling is 6,000 segments a day to the US and 2,000 a day to T-Mobile, at 3.75 messages per second.
Is a toll-free number cheaper than 10DLC for an AI SMS agent?
Not obviously. On Twilio the toll-free carrier fee schedule matches long code except that US Cellular outbound is US$0.0045 rather than US$0.005, the number costs US$2.15 a month against US$1.15, and it still requires verification. From 15 September 2026 Twilio requires separate Privacy Policy and Terms and Conditions URL fields on new toll-free verification submissions, with missing links rejected under error 30493.