How to Send Mass Text Messages the Legal Way

To send mass text messages legally, you need four things before the first message leaves your system: documented opt-in consent from every recipient, a registered sending route (A2P 10DLC, verified toll-free, or a short code), automatic opt-out handling, and a clean list. Everything else — the broadcast tool, the scheduling, the templates — sits on top of that foundation. Skip any piece of it and your campaign is either illegal, undeliverable, or both.

There is no shortage of tools promising “bulk text” or “SMS broadcast” in three clicks. What they rarely explain is what has to exist underneath: mass texting to US consumers is A2P messaging, and the carriers treat it as a regulated traffic class, not a bigger version of texting from your phone. SIPNEX is an FCC-licensed carrier that provides SMS and MMS messaging and handles the registration layer on behalf of our customers. This guide covers the compliance spine first — because that is what actually determines whether your messages arrive — then the mechanics.

This article is informational, not legal advice. For consent and revocation questions specific to your operation, involve counsel.

Consent comes first: the TCPA layer

Before route selection, before throughput, before anything: every number on your list needs consent that matches the message type you are sending.

Marketing texts require prior express written consent — the recipient affirmatively agreed, in a signed or recorded form, to receive marketing messages from your business specifically. A web form with a clear disclosure, a text-to-join keyword with a confirmation message, or a point-of-sale opt-in all work when documented properly. Transactional messages (order confirmations, appointment reminders, account alerts) require prior express consent, a lower bar, but still consent. A purchased list carries neither. The operational details overlap heavily with voice rules — our TCPA compliance checklist covers the consent framework, documentation, and penalty exposure in depth.

Two practical rules follow from this. First, keep consent records: when, where, and how each recipient opted in, and what they opted in to. If a complaint or demand letter arrives, your consent log is the defense. Second, do not stretch consent across purposes. Someone who opted in to shipping notifications did not opt in to your flash-sale broadcast — and mixing the two on one number is also a registration problem, as covered below.

Opt-out handling and quiet hours

Every mass text needs a working exit. At minimum, your system must honor STOP replies immediately — the number is suppressed, a single confirmation message goes out, and nothing further is sent. Carriers monitor opt-out compliance, and failing to honor STOP can get a campaign suspended. Under the FCC’s revocation rules, consumers can also revoke consent with words like “quit,” “end,” “revoke,” “opt out,” “cancel,” and “unsubscribe,” so keyword handling that only matches STOP is not enough. Our A2P 10DLC news tracker follows the FCC’s revocation timeline, including the revoke-all provision currently slated for January 2027.

Include opt-out language in the message itself — “Reply STOP to unsubscribe” — and identify your business by name so the recipient knows who is texting. Then respect the clock: most carriers define quiet hours, typically 9 PM to 8 AM in the recipient’s local time zone. A broadcast queued at 6 PM Eastern that is still draining at midnight is sending into quiet hours for every West Coast number that came earlier in the list and every East Coast number still queued. Schedule with the slowest-delivering time zone in mind.

Choosing a route: 10DLC, toll-free, or short code

Mass texting rides on one of three number types, and the choice is driven by volume, use case, and how local you need to look.

A2P 10DLC — a standard 10-digit local number, registered through The Campaign Registry. This is the default route for most businesses: local presence, support for two-way conversation, and per-message costs at the low end of the range. Registration means a brand filing (your legal identity, vetted into a trust score) and a campaign filing per use case, with a small one-time brand fee and a recurring campaign fee — typically $10 per month per campaign for standard use cases, billed monthly. The full process — vetting timelines, trust scores, surcharges — is in our step-by-step A2P 10DLC registration guide.

Verified toll-free — an 800-series number verified directly with the carriers rather than through TCR. Simpler verification, appropriate for national brands and customer-service notifications, with per-message rates typically slightly higher than 10DLC. The tradeoff is recognition: recipients are generally less likely to engage with a toll-free sender than a local one for local-feeling use cases.

Short code — a 5-6 digit number built for high-volume, one-way broadcast. Short codes carry the highest throughput of the three routes and make sense for large-scale marketing programs, but they are the most expensive option and are overkill for most operations. If your volume genuinely exceeds what a registered 10DLC campaign delivers, that is the conversation to have with your provider before defaulting to a short code.

One structural rule applies regardless of route: one campaign per use case, and each phone number attaches to exactly one campaign. Marketing and transactional traffic belong on separate numbers with separate registrations.

Throughput: how fast a mass text actually goes out

“Send to 50,000 people” does not mean 50,000 messages leave simultaneously. On 10DLC, your TCR trust score pins you somewhere between 1 and 75 messages per second, while short codes can handle hundreds per second. At 10 messages per second, a 50,000-message broadcast takes about 83 minutes to drain. That math matters for time-sensitive sends and for the quiet-hours problem above.

Two consequences. First, do not try to outrun your assigned throughput — excess messages get queued or dropped, and consistently exceeding limits gets your campaign flagged for review. Second, if your legitimate volume needs exceed your current tier, the fix is registration-side (vetting, campaign structure, or a different route), not spraying traffic across a pile of unregistered numbers. That pattern — carriers call it snowshoeing — is one that carrier filtering reliably catches, and it burns the numbers along with the campaign. For very high-volume operations (100K+ messages), talk to your provider about throughput optimization and campaign structure before launch.

Cost scales with segments, not messages: a single SMS segment is 160 GSM-7 characters (70 with Unicode — one emoji cuts the limit), and a 161-character message bills as two segments. Base rates typically run $0.005 to $0.02 per SMS segment, with carrier surcharges on top. At broadcast volume, a template that fits one segment instead of two roughly halves the send cost — the full segment math and the MMS tradeoff are in our SMS vs MMS comparison.

List hygiene before you hit send

A mass text is only as good as the list behind it, and dirty lists create both waste and risk.

Suppress every prior opt-out before every send — not just STOP replies, but every revocation keyword, across your whole business. Remove landlines: MMS cannot reach them, and SMS behavior varies by carrier; number-type identification lets you segment mobile from landline before sending. Drop numbers that have hard-failed on previous sends — repeatedly texting dead numbers is a spam signal. And never send to a purchased or scraped list; beyond the consent problem, those lists are salted with litigation traps and abuse-report magnets.

Content hygiene matters too, because carrier filters score the message along with the sender. Avoid URL shorteners (use your full domain), skip the ALL-CAPS urgency phrasing that spam filters key on, keep volume per number consistent rather than spiky, and watch per-carrier delivery rates — a sudden drop on one carrier usually means your content tripped a filter. T-Mobile is the strictest filter of the majors: clean delivery there is the strongest signal your content will clear AT&T and Verizon too.

What “SMS broadcast” actually requires underneath

Strip away the interface and an SMS broadcast is registered A2P traffic on real routes: a vetted brand, an approved campaign that matches what you are actually sending, numbers associated with that campaign, throughput assigned by trust score, and delivery through carrier-connected infrastructure with opt-out processing built in. Whether you trigger it from a dashboard or programmatically through an SMS API, that underlying stack is identical — and it is the part your broadcast tool cannot fake.

This is also why “how to send mass texts without getting blocked” has only one honest answer: register, get consent, and send content that matches your campaign. Unregistered bulk traffic on 10DLC numbers is filtered or silently dropped by the major carriers — your platform reports “sent” while the recipient gets nothing. Grey routes, number rotation to dodge filters, and consent-free “data providers” are not shortcuts; they are how legitimate businesses end up with blocked campaigns and TCPA exposure. The registered path costs a small filing fee and a few days of vetting. The evasive path costs the campaign.

Frequently asked questions

Mass texting done right is registered traffic, real consent, and clean lists — the parts that determine whether your broadcast actually arrives. SIPNEX provides SMS and MMS messaging as an FCC-licensed carrier, with A2P 10DLC registration handled on your behalf, automatic opt-out processing, and carrier surcharges itemized separately. Set up business messaging or call (833) 665-2220.