SMS API Pricing in 2026: Cost Per Message vs. Cost Per Verification
Real per-message rates and carrier fees from five providers, plus the formula for calculating what a completed verification actually costs.
Rowan Haddad
Content & SEO Manager
Summary
SMS API pricing is usually quoted per message, but that isn't always the number that matters. For authentication, the more useful metric is cost per completed verification. A published SMS rate tells you what one message costs. It doesn't tell you what it costs to get a real user through signup or login, because a verification can require multiple SMS attempts, separately billed messaging and carrier fees may apply to each attempt, and fixed platform or registration costs can add to the total.
SMS has been the default channel for one-time passcodes and account verification for well over a decade, and most teams building an authentication flow assume the pricing is as simple as the number on a provider's homepage. It usually isn't. Between carrier surcharges, country-specific registration requirements, and the fact that verification pricing is structured differently from raw messaging pricing, the actual invoice for an SMS-based auth flow can look very different from the quoted rate, and it varies more by destination and by attempt count than most teams expect going in.
This guide breaks down both sides of the equation: what an SMS API can actually cost once carrier fees, registration, segmentation, and number costs are included, and how to calculate the effective cost of completing an OTP verification.
For a general introduction to SMS APIs, see what an SMS API is. If you're comparing providers, see the best SMS API providers. This guide focuses specifically on pricing and verification economics.
What Does an SMS Actually Cost?
US SMS rates vary by provider and can change based on the destination network, sender type, volume, and applicable surcharges, and are intended as reference prices, not guaranteed quotes.
Provider | Published US SMS rate | Pricing model |
|---|---|---|
Infobip | $0.00818* | Country-level average across supported networks |
Plivo | $0.0077 | Published base rate; $0.0079 for toll-free; carrier surcharges apply, see below |
Sinch | $0.0078 | Published base rate; $0.009 for short code; carrier surcharges apply, see below |
Twilio | $0.0083 | US outbound SMS base rate; carrier surcharges apply, see below |
*Infobip displays an average price across supported networks for each country. The exact price can vary by destination network and applicable discounts, with per-network pricing available in its Portal. The figure above is the price shown when its calculator is set to USD.
These numbers are base or published rates, not necessarily the final amount on an invoice. Prelude also offers a standalone SMS API, but it isn't included in the table above since Prelude doesn't publish one flat all-in rate the way the four providers here do; its pricing structure is covered later in this guide, alongside how its Verify product prices verification.
Carrier surcharges can change the effective rate
For Twilio, Plivo, and Sinch, carrier surcharges are listed separately from the published base rate. Infobip presents its US figure differently, as an average across supported networks.
For example, the following carrier surcharges are listed by Twilio:
Carrier | Outbound surcharge | Inbound surcharge |
|---|---|---|
AT&T | $0.0035 | $0.0035 |
T-Mobile | $0.0045 | $0.0025 |
Verizon | $0.0045 | — |
US Cellular | $0.005 | $0.0025 |
That means a US SMS sent through Twilio to a T-Mobile subscriber starts at $0.0128 before other applicable costs: $0.0083 base SMS rate plus a $0.0045 carrier surcharge.
The important point is that a headline rate such as "$0.0083 per SMS" isn't necessarily the same as the amount you'll pay for every delivered message.
Why the Headline SMS Rate Isn't Your Real Cost
Several additional factors can increase the effective cost of an SMS API:
Registration and compliance fees
Applications sending A2P SMS/MMS to US recipients over 10-digit long-code numbers generally need A2P 10DLC registration.
Registration can add one-time and recurring costs, depending on the brand type, campaign, and messaging provider. For example, Twilio currently lists different registration costs for sole proprietors, low-volume standard brands, and standard brands, including brand registration, campaign vetting, and recurring campaign fees. Providers can pass registration and campaign-related costs through to customers and may also charge their own fees on top.
These costs matter most at lower volumes. A registration or campaign fee that's negligible across millions of messages can materially affect the effective cost of a small messaging program.
Registration requirements and fees can change, so check the provider's current A2P 10DLC pricing before using a fixed figure in a cost model. For the full registration process and eligibility requirements, see our 10DLC guide.
Message segmentation
SMS is billed by segment, not by the message as it appears in your application.
A single-segment GSM-7 SMS can contain up to 160 characters. Once a message is concatenated across multiple segments, the limit falls to 153 characters per segment.
Unicode/UCS-2 messages can contain up to 70 characters in one segment, with fewer characters available per segment when concatenated.
An OTP such as:
Your verification code is 483921.
will normally fit comfortably within one segment. Longer transactional messages, emojis, or non-Latin characters can cause a message to become multiple billable segments.
The result is simple: one API call does not necessarily equal one billable SMS segment.
Number costs
Phone numbers can add a recurring cost to an SMS API implementation. For example:
Twilio: $1.15/month for a long code
Plivo: $0.50/month
For high-volume messaging, number rental is usually small compared with message costs. At low volumes, however, fixed number costs can have a noticeable effect on the effective cost per message.
Provider markup and platform fees
Providers use different pricing structures. Some incorporate their margin directly into the SMS rate. Others, like Prelude, separate carrier messaging costs (billed at cost, no markup) from a distinct platform or verification fee.
That distinction becomes particularly important when comparing SMS APIs with verification APIs. A low SMS rate does not automatically mean a low cost per successful authentication.
Failed messages can still cost money
Some providers charge separately for failed-message processing. For example, Twilio currently applies a $0.001 fee to messages that terminate in a "Failed" status.
It's a small amount, but it illustrates the larger point: message cost and successful-outcome cost are different metrics.
SMS Pricing Varies Dramatically by Country
US pricing is only one part of the picture. International SMS rates can vary substantially by destination. The following are Prelude's published message rates, which Prelude describes as carrier cost with no markup. Check the live rate calculator before using these figures for budgeting.
Country | SMS rate |
|---|---|
United States | €0.0043 |
United Kingdom | €0.0266 |
France | €0.03 |
Germany | €0.0582 |
India | €0.0357 |
Malaysia | €0.1846 |
Sender registration and compliance requirements vary by country, sender type, and traffic type. Check the current requirements before launching messaging in a new market.
At these published rates, one SMS to Malaysia costs roughly 43× the US rate. Germany costs roughly 13.5× the US rate.
The difference isn't simply a question of which country has "cheaper SMS." Destination-carrier pricing, local routing, regulations, sender requirements, and market structure all contribute to the final rate. That is why a US SMS quote is a poor proxy for the cost of an international authentication program.
Prelude publishes rates across all 230 supported destinations on its country pricing pages.
For Verification, Cost Per SMS Isn't Enough
For many messaging use cases, cost per SMS is a useful budgeting metric. For authentication, however, it isn't enough.
A user might request a code, fail to receive it, request another, mistype the code, and finally complete verification on a later attempt. Each additional SMS can create another messaging charge. Verification traffic can also include automated abuse such as SMS pumping, where fraudulent traffic generates paid OTP requests without representing genuine users. This is where a provider's incentive structure matters: because Prelude's revenue comes from the verification rather than the message, it isn't rewarded for higher traffic, so catching pumping and abusive requests before they become billable protects both the invoice and the conversion funnel, rather than treating every attempt as revenue.
The useful question therefore becomes: how much does it cost to complete one verification successfully? That number depends on the provider, destination, carrier, verification model, and number of SMS attempts.
How to Calculate Cost Per Completed Verification
For a forward-looking estimate, the most robust way to think about this is:
Effective cost per completed verification = total authentication spend ÷ completed verifications
That handles retries, failures, and fixed costs naturally. To model that spend before you have real usage data, break it down as: verification/platform fee + message costs for all attempts + applicable carrier surcharges + allocated registration, number, and platform costs.
Example: Twilio Verify
Twilio Verify currently charges $0.05 per successful verification plus standard channel fees. For US SMS, Twilio lists an additional $0.0083 per SMS. Twilio also states that SMS attempts are charged, and a verification can involve multiple send attempts.
Using the published US rates:
One SMS attempt: $0.05 verification fee + $0.0083 SMS = $0.0583
Two SMS attempts: $0.05 verification fee + $0.0166 SMS (2 × $0.0083) = $0.0666
The second scenario is about 14% more expensive because the additional SMS attempt adds another channel charge. Twilio's general US SMS pricing also lists carrier surcharges by destination carrier (for example, $0.0045 for T-Mobile), but those apply to Twilio's standard Messaging API pricing; the Verify pricing page doesn't explicitly confirm whether that same surcharge is added on top of the $0.0083 Verify channel fee. Confirm this against your specific Verify configuration before including it in a cost model.
These are illustrative calculations, not universal costs. The broader point holds regardless: quoting "$0.0583 per verification" assumes exactly one SMS attempt. A retry-heavy authentication flow can have a materially higher effective cost.
Example: Prelude Verify
Prelude's Pay As You Go plan charges €0.032 per verification, with message costs billed separately at carrier cost. For a US SMS at the published €0.0043 rate:
One SMS attempt: €0.032 verification + €0.0043 SMS = €0.0363
Two SMS attempts: €0.032 verification + €0.0086 SMS (2 × €0.0043) = €0.0406
Under this pricing model, the verification fee remains fixed while separately billed messaging costs increase with the number of attempts. Prelude's pricing page states directly, "you pay exactly what carriers charge with no margin added," which is the source for describing its country rates as carrier cost with no markup.
How Verification Pricing Models Differ
Verification APIs don't all charge in exactly the same way.
Provider | Verification fee | Channel/message fees |
|---|---|---|
Twilio Verify | $0.05/successful verification | $0.0083/SMS in the US; applicable channel fees may apply |
Vonage Verify Conversion | $0.06084 (€0.052)/successful verification | Additional messaging and voice rates apply |
Prelude Verify | €0.032/verification | Country-specific message cost |
Twilio charges its verification fee when verification succeeds. Vonage's default Verify Conversion model also charges based on successful conversion, though it separately offers a Verify Success model with a different charging model.
Prelude's public pricing describes the charge as per verification, rather than using the same "successful verification" terminology as Twilio or Vonage. The wording and billing mechanics therefore aren't directly interchangeable.
Worth noting separately from the verification fee itself: Twilio's own pricing page states that SMS message attempts "are always charged and not subject to delivery," and a Verify session can include up to five send attempts by default. That means a string of SMS attempts that never reach the user, or a verification the user never completes, can still generate SMS channel charges even though the $0.05 verification fee only applies on success.
One practical advantage of Prelude's model comes down to how it defines a single verification. A verification window opens when a code is first requested for a phone number, and any further attempts for that same number within the window count as retries on the same verification rather than a new one; the window closes once it expires (five minutes by default, configurable per account) or the user successfully enters the code. In practice, that means a user who mistypes a code or asks for a resend doesn't cost extra on the platform fee, only the additional message. The worked examples earlier in this guide reflect this directly: the same €0.032 fee applies whether it took one SMS attempt or two.
To sum up, when comparing providers, look beyond the advertised verification fee and check:
What counts as a billable verification?
Are unsuccessful attempts charged?
Are SMS messages charged separately?
Are carrier fees passed through?
How are retries billed, and do they fall inside a defined window or count as new verifications?
Are voice or alternative channels priced separately?
Are registration and number costs additional?
How Prelude Prices Verification
Prelude's Pay As You Go plan charges €0.032 per verification, with message costs billed separately at carrier cost and no markup on the message itself.
Using the worked examples from earlier in this guide: a US verification with one SMS attempt costs €0.0363 on Prelude, roughly $0.042 at recent exchange rates, versus $0.0583 on Twilio Verify for the same single-attempt scenario. That gap comes from Prelude's lower platform fee and from billing messages at carrier cost with no markup, rather than folding a margin into the per-message rate. Teams migrating specifically from Twilio can see a fuller side-by-side in our Twilio alternative guide.
On average, customers cut their SMS costs by 60% when they switch to Prelude.
In addition, Prelude supports SMS, WhatsApp, RCS, Telegram, and Viber across 230 destinations, with country-level rates available on its countries page.
For customers with larger volumes, committed usage unlocks lower per-unit rates across tiers. Enterprise customers can negotiate committed-volume pricing directly.
Prelude's Startup plan is €360/month and includes features such as custom sender ID, Slack support, advanced antifraud, and six months of data history. Enterprise plans add features including a 99.95% SLA, dedicated support, and post-payment billing.
Prelude's standalone SMS API, for sending outside of Verify, prices differently. Its default Pay-As-You-Go plan charges the public carrier price per SMS with no margin, the same pass-through principle as Verify, plus a separate service license fee per message, with no subscription or commitment required. A License Plan is available for consistent or high-volume senders, moving to post-paid monthly invoicing with discounted per-SMS fees and custom volume tiers. Full details are on the SMS API page.
See the pricing page for current plan details and the live rate calculator.
The Simplest Way to Compare SMS API Costs
When evaluating SMS API pricing, don't compare providers using the headline SMS rate alone. Use a three-step calculation:
Calculate the true cost of one SMS segment in each destination, including applicable carrier surcharges.
Estimate the average number of attempts per successful verification.
Add verification, platform, registration, number, and other fixed costs.
That's what feeds into the effective cost per completed verification, and it's the number that tells you what you're actually paying to get users through the authentication flow.
FAQs
What's the difference between cost per message and cost per verification?
Cost per message generally refers to the charge for an individual SMS segment. Cost per completed verification is the total cost of getting a user through the authentication flow. A verification can require multiple SMS attempts, so its effective cost can be higher than the price of one message.
Is SMS pricing based on messages or segments?
Segments. A GSM-7 message can contain up to 160 characters in a single segment, or 153 characters per segment when concatenated. Unicode messages can contain up to 70 characters in a single segment, with fewer characters available per segment when concatenated. Providers generally bill according to the number of segments sent.
How much does one SMS verification actually cost?
There isn't one universal number. It depends on the provider, destination, carrier, verification fee, and number of attempts. Using the illustrative Twilio US example above, one successful verification with one SMS attempt costs about $0.0583. Two attempts increase that to about $0.0666. Carrier surcharges and other applicable fees can add further to these figures depending on your specific configuration.
Do SMS API providers charge for failed or retried messages?
It varies by provider and pricing model. Some providers charge for SMS attempts regardless of whether the user eventually completes verification. Providers may also apply separate fees to messages that fail delivery. The practical takeaway is that retry-heavy authentication traffic can cost more than a one-message estimate suggests.
Are carrier fees included in SMS API prices?
Not always. Twilio, Plivo, and Sinch list carrier surcharges separately from their base SMS rates. Infobip presents its country pricing differently, showing an average across supported networks. Always check whether a quoted SMS rate is an all-in price or a base rate before comparing providers.
Do SMS API providers offer volume discounts?
Yes, although the structure varies. Some providers publish automatic volume tiers or offer committed-use discounts. Others advertise volume pricing without publishing all breakpoints. For a meaningful comparison, calculate pricing at your actual monthly volume and destination mix, rather than comparing the lowest advertised rate.
Start Optimizing Your Authentication Costs
The cost of an OTP flow is more than the price of one SMS. Compare the full economics: destination rates, carrier costs, retries, verification fees, and the number of successful verifications you generate.
Prelude supports verification across 230 destinations with carrier-cost messaging, no markup on the message itself, and a lower platform fee than the Twilio Verify example worked through above.
See pricing and rates by country or book a demo to model your specific countries and volumes.
SMS has been the default channel for one-time passcodes and account verification for well over a decade, and most teams building an authentication flow assume the pricing is as simple as the number on a provider's homepage. It usually isn't. Between carrier surcharges, country-specific registration requirements, and the fact that verification pricing is structured differently from raw messaging pricing, the actual invoice for an SMS-based auth flow can look very different from the quoted rate, and it varies more by destination and by attempt count than most teams expect going in.
This guide breaks down both sides of the equation: what an SMS API can actually cost once carrier fees, registration, segmentation, and number costs are included, and how to calculate the effective cost of completing an OTP verification.
For a general introduction to SMS APIs, see what an SMS API is. If you're comparing providers, see the best SMS API providers. This guide focuses specifically on pricing and verification economics.
What Does an SMS Actually Cost?
US SMS rates vary by provider and can change based on the destination network, sender type, volume, and applicable surcharges, and are intended as reference prices, not guaranteed quotes.
Provider | Published US SMS rate | Pricing model |
|---|---|---|
Infobip | $0.00818* | Country-level average across supported networks |
Plivo | $0.0077 | Published base rate; $0.0079 for toll-free; carrier surcharges apply, see below |
Sinch | $0.0078 | Published base rate; $0.009 for short code; carrier surcharges apply, see below |
Twilio | $0.0083 | US outbound SMS base rate; carrier surcharges apply, see below |
*Infobip displays an average price across supported networks for each country. The exact price can vary by destination network and applicable discounts, with per-network pricing available in its Portal. The figure above is the price shown when its calculator is set to USD.
These numbers are base or published rates, not necessarily the final amount on an invoice. Prelude also offers a standalone SMS API, but it isn't included in the table above since Prelude doesn't publish one flat all-in rate the way the four providers here do; its pricing structure is covered later in this guide, alongside how its Verify product prices verification.
Carrier surcharges can change the effective rate
For Twilio, Plivo, and Sinch, carrier surcharges are listed separately from the published base rate. Infobip presents its US figure differently, as an average across supported networks.
For example, the following carrier surcharges are listed by Twilio:
Carrier | Outbound surcharge | Inbound surcharge |
|---|---|---|
AT&T | $0.0035 | $0.0035 |
T-Mobile | $0.0045 | $0.0025 |
Verizon | $0.0045 | — |
US Cellular | $0.005 | $0.0025 |
That means a US SMS sent through Twilio to a T-Mobile subscriber starts at $0.0128 before other applicable costs: $0.0083 base SMS rate plus a $0.0045 carrier surcharge.
The important point is that a headline rate such as "$0.0083 per SMS" isn't necessarily the same as the amount you'll pay for every delivered message.
Why the Headline SMS Rate Isn't Your Real Cost
Several additional factors can increase the effective cost of an SMS API:
Registration and compliance fees
Applications sending A2P SMS/MMS to US recipients over 10-digit long-code numbers generally need A2P 10DLC registration.
Registration can add one-time and recurring costs, depending on the brand type, campaign, and messaging provider. For example, Twilio currently lists different registration costs for sole proprietors, low-volume standard brands, and standard brands, including brand registration, campaign vetting, and recurring campaign fees. Providers can pass registration and campaign-related costs through to customers and may also charge their own fees on top.
These costs matter most at lower volumes. A registration or campaign fee that's negligible across millions of messages can materially affect the effective cost of a small messaging program.
Registration requirements and fees can change, so check the provider's current A2P 10DLC pricing before using a fixed figure in a cost model. For the full registration process and eligibility requirements, see our 10DLC guide.
Message segmentation
SMS is billed by segment, not by the message as it appears in your application.
A single-segment GSM-7 SMS can contain up to 160 characters. Once a message is concatenated across multiple segments, the limit falls to 153 characters per segment.
Unicode/UCS-2 messages can contain up to 70 characters in one segment, with fewer characters available per segment when concatenated.
An OTP such as:
Your verification code is 483921.
will normally fit comfortably within one segment. Longer transactional messages, emojis, or non-Latin characters can cause a message to become multiple billable segments.
The result is simple: one API call does not necessarily equal one billable SMS segment.
Number costs
Phone numbers can add a recurring cost to an SMS API implementation. For example:
Twilio: $1.15/month for a long code
Plivo: $0.50/month
For high-volume messaging, number rental is usually small compared with message costs. At low volumes, however, fixed number costs can have a noticeable effect on the effective cost per message.
Provider markup and platform fees
Providers use different pricing structures. Some incorporate their margin directly into the SMS rate. Others, like Prelude, separate carrier messaging costs (billed at cost, no markup) from a distinct platform or verification fee.
That distinction becomes particularly important when comparing SMS APIs with verification APIs. A low SMS rate does not automatically mean a low cost per successful authentication.
Failed messages can still cost money
Some providers charge separately for failed-message processing. For example, Twilio currently applies a $0.001 fee to messages that terminate in a "Failed" status.
It's a small amount, but it illustrates the larger point: message cost and successful-outcome cost are different metrics.
SMS Pricing Varies Dramatically by Country
US pricing is only one part of the picture. International SMS rates can vary substantially by destination. The following are Prelude's published message rates, which Prelude describes as carrier cost with no markup. Check the live rate calculator before using these figures for budgeting.
Country | SMS rate |
|---|---|
United States | €0.0043 |
United Kingdom | €0.0266 |
France | €0.03 |
Germany | €0.0582 |
India | €0.0357 |
Malaysia | €0.1846 |
Sender registration and compliance requirements vary by country, sender type, and traffic type. Check the current requirements before launching messaging in a new market.
At these published rates, one SMS to Malaysia costs roughly 43× the US rate. Germany costs roughly 13.5× the US rate.
The difference isn't simply a question of which country has "cheaper SMS." Destination-carrier pricing, local routing, regulations, sender requirements, and market structure all contribute to the final rate. That is why a US SMS quote is a poor proxy for the cost of an international authentication program.
Prelude publishes rates across all 230 supported destinations on its country pricing pages.
For Verification, Cost Per SMS Isn't Enough
For many messaging use cases, cost per SMS is a useful budgeting metric. For authentication, however, it isn't enough.
A user might request a code, fail to receive it, request another, mistype the code, and finally complete verification on a later attempt. Each additional SMS can create another messaging charge. Verification traffic can also include automated abuse such as SMS pumping, where fraudulent traffic generates paid OTP requests without representing genuine users. This is where a provider's incentive structure matters: because Prelude's revenue comes from the verification rather than the message, it isn't rewarded for higher traffic, so catching pumping and abusive requests before they become billable protects both the invoice and the conversion funnel, rather than treating every attempt as revenue.
The useful question therefore becomes: how much does it cost to complete one verification successfully? That number depends on the provider, destination, carrier, verification model, and number of SMS attempts.
How to Calculate Cost Per Completed Verification
For a forward-looking estimate, the most robust way to think about this is:
Effective cost per completed verification = total authentication spend ÷ completed verifications
That handles retries, failures, and fixed costs naturally. To model that spend before you have real usage data, break it down as: verification/platform fee + message costs for all attempts + applicable carrier surcharges + allocated registration, number, and platform costs.
Example: Twilio Verify
Twilio Verify currently charges $0.05 per successful verification plus standard channel fees. For US SMS, Twilio lists an additional $0.0083 per SMS. Twilio also states that SMS attempts are charged, and a verification can involve multiple send attempts.
Using the published US rates:
One SMS attempt: $0.05 verification fee + $0.0083 SMS = $0.0583
Two SMS attempts: $0.05 verification fee + $0.0166 SMS (2 × $0.0083) = $0.0666
The second scenario is about 14% more expensive because the additional SMS attempt adds another channel charge. Twilio's general US SMS pricing also lists carrier surcharges by destination carrier (for example, $0.0045 for T-Mobile), but those apply to Twilio's standard Messaging API pricing; the Verify pricing page doesn't explicitly confirm whether that same surcharge is added on top of the $0.0083 Verify channel fee. Confirm this against your specific Verify configuration before including it in a cost model.
These are illustrative calculations, not universal costs. The broader point holds regardless: quoting "$0.0583 per verification" assumes exactly one SMS attempt. A retry-heavy authentication flow can have a materially higher effective cost.
Example: Prelude Verify
Prelude's Pay As You Go plan charges €0.032 per verification, with message costs billed separately at carrier cost. For a US SMS at the published €0.0043 rate:
One SMS attempt: €0.032 verification + €0.0043 SMS = €0.0363
Two SMS attempts: €0.032 verification + €0.0086 SMS (2 × €0.0043) = €0.0406
Under this pricing model, the verification fee remains fixed while separately billed messaging costs increase with the number of attempts. Prelude's pricing page states directly, "you pay exactly what carriers charge with no margin added," which is the source for describing its country rates as carrier cost with no markup.
How Verification Pricing Models Differ
Verification APIs don't all charge in exactly the same way.
Provider | Verification fee | Channel/message fees |
|---|---|---|
Twilio Verify | $0.05/successful verification | $0.0083/SMS in the US; applicable channel fees may apply |
Vonage Verify Conversion | $0.06084 (€0.052)/successful verification | Additional messaging and voice rates apply |
Prelude Verify | €0.032/verification | Country-specific message cost |
Twilio charges its verification fee when verification succeeds. Vonage's default Verify Conversion model also charges based on successful conversion, though it separately offers a Verify Success model with a different charging model.
Prelude's public pricing describes the charge as per verification, rather than using the same "successful verification" terminology as Twilio or Vonage. The wording and billing mechanics therefore aren't directly interchangeable.
Worth noting separately from the verification fee itself: Twilio's own pricing page states that SMS message attempts "are always charged and not subject to delivery," and a Verify session can include up to five send attempts by default. That means a string of SMS attempts that never reach the user, or a verification the user never completes, can still generate SMS channel charges even though the $0.05 verification fee only applies on success.
One practical advantage of Prelude's model comes down to how it defines a single verification. A verification window opens when a code is first requested for a phone number, and any further attempts for that same number within the window count as retries on the same verification rather than a new one; the window closes once it expires (five minutes by default, configurable per account) or the user successfully enters the code. In practice, that means a user who mistypes a code or asks for a resend doesn't cost extra on the platform fee, only the additional message. The worked examples earlier in this guide reflect this directly: the same €0.032 fee applies whether it took one SMS attempt or two.
To sum up, when comparing providers, look beyond the advertised verification fee and check:
What counts as a billable verification?
Are unsuccessful attempts charged?
Are SMS messages charged separately?
Are carrier fees passed through?
How are retries billed, and do they fall inside a defined window or count as new verifications?
Are voice or alternative channels priced separately?
Are registration and number costs additional?
How Prelude Prices Verification
Prelude's Pay As You Go plan charges €0.032 per verification, with message costs billed separately at carrier cost and no markup on the message itself.
Using the worked examples from earlier in this guide: a US verification with one SMS attempt costs €0.0363 on Prelude, roughly $0.042 at recent exchange rates, versus $0.0583 on Twilio Verify for the same single-attempt scenario. That gap comes from Prelude's lower platform fee and from billing messages at carrier cost with no markup, rather than folding a margin into the per-message rate. Teams migrating specifically from Twilio can see a fuller side-by-side in our Twilio alternative guide.
On average, customers cut their SMS costs by 60% when they switch to Prelude.
In addition, Prelude supports SMS, WhatsApp, RCS, Telegram, and Viber across 230 destinations, with country-level rates available on its countries page.
For customers with larger volumes, committed usage unlocks lower per-unit rates across tiers. Enterprise customers can negotiate committed-volume pricing directly.
Prelude's Startup plan is €360/month and includes features such as custom sender ID, Slack support, advanced antifraud, and six months of data history. Enterprise plans add features including a 99.95% SLA, dedicated support, and post-payment billing.
Prelude's standalone SMS API, for sending outside of Verify, prices differently. Its default Pay-As-You-Go plan charges the public carrier price per SMS with no margin, the same pass-through principle as Verify, plus a separate service license fee per message, with no subscription or commitment required. A License Plan is available for consistent or high-volume senders, moving to post-paid monthly invoicing with discounted per-SMS fees and custom volume tiers. Full details are on the SMS API page.
See the pricing page for current plan details and the live rate calculator.
The Simplest Way to Compare SMS API Costs
When evaluating SMS API pricing, don't compare providers using the headline SMS rate alone. Use a three-step calculation:
Calculate the true cost of one SMS segment in each destination, including applicable carrier surcharges.
Estimate the average number of attempts per successful verification.
Add verification, platform, registration, number, and other fixed costs.
That's what feeds into the effective cost per completed verification, and it's the number that tells you what you're actually paying to get users through the authentication flow.
FAQs
What's the difference between cost per message and cost per verification?
Cost per message generally refers to the charge for an individual SMS segment. Cost per completed verification is the total cost of getting a user through the authentication flow. A verification can require multiple SMS attempts, so its effective cost can be higher than the price of one message.
Is SMS pricing based on messages or segments?
Segments. A GSM-7 message can contain up to 160 characters in a single segment, or 153 characters per segment when concatenated. Unicode messages can contain up to 70 characters in a single segment, with fewer characters available per segment when concatenated. Providers generally bill according to the number of segments sent.
How much does one SMS verification actually cost?
There isn't one universal number. It depends on the provider, destination, carrier, verification fee, and number of attempts. Using the illustrative Twilio US example above, one successful verification with one SMS attempt costs about $0.0583. Two attempts increase that to about $0.0666. Carrier surcharges and other applicable fees can add further to these figures depending on your specific configuration.
Do SMS API providers charge for failed or retried messages?
It varies by provider and pricing model. Some providers charge for SMS attempts regardless of whether the user eventually completes verification. Providers may also apply separate fees to messages that fail delivery. The practical takeaway is that retry-heavy authentication traffic can cost more than a one-message estimate suggests.
Are carrier fees included in SMS API prices?
Not always. Twilio, Plivo, and Sinch list carrier surcharges separately from their base SMS rates. Infobip presents its country pricing differently, showing an average across supported networks. Always check whether a quoted SMS rate is an all-in price or a base rate before comparing providers.
Do SMS API providers offer volume discounts?
Yes, although the structure varies. Some providers publish automatic volume tiers or offer committed-use discounts. Others advertise volume pricing without publishing all breakpoints. For a meaningful comparison, calculate pricing at your actual monthly volume and destination mix, rather than comparing the lowest advertised rate.
Start Optimizing Your Authentication Costs
The cost of an OTP flow is more than the price of one SMS. Compare the full economics: destination rates, carrier costs, retries, verification fees, and the number of successful verifications you generate.
Prelude supports verification across 230 destinations with carrier-cost messaging, no markup on the message itself, and a lower platform fee than the Twilio Verify example worked through above.
See pricing and rates by country or book a demo to model your specific countries and volumes.
Start optimizing your auth flow
Send verification text-messages anywhere in the world with the best price, the best deliverability and no spam.
