Sending…

Every code, every broadcast, every delivery accounted for.

Send one-time passcodes and SMS or email broadcasts through one API. Direct carrier routes across five African markets, SMS to 30 more countries, email to any inbox, and signed webhooks back to your stack.

Get started Read the docs

OTP · smsPOST /v1/otp/send

+220 87 712 3456

Your verification code is 482913

Webhook142ms

otp.verified

X-Transmit-Signature:
t=1759312804,v1=9f3a…c21e

200 OK

Broadcast · smsScheduled 09:00

Tobaski sale starts today — 20% off everything until Sunday.

4,812 delivered61 failed5,000 recipients

Broadcast · email

Your September statement is ready

1,240 recipients0 suppressed

Completed

RecipientDelivered

+220 86 612 3456

Direct carrier route · Gambia

Queued09:41:02
Sent09:41:02
Delivered09:41:04

Direct carrier routes across

+220Gambia
+221Senegal
+234Nigeria
+233Ghana
+254Kenya

What it is

Transmit is one API for every message your product has to get right — passcodes, broadcasts, and the webhooks that report back. One key to send, one dashboard to see exactly what landed.

Core problems

The problem we solve

01 / 03

Codes that never arrive

An OTP stuck on a grey route is a signup you never see. Users tap resend twice, then leave — and nothing tells you which carrier dropped it.

02 / 03

Broadcasts nobody can account for

You send to five thousand numbers and get back a single “accepted”. Which ones landed, which failed and why stays a mystery until customers complain.

03 / 03

Webhooks you can’t trust

Events arrive twice, out of order or not at all, and anyone who finds the URL can post to it. Your backend is left guessing what actually happened.

What Transmit does

Four things. One API.

Direct routes across five African markets

Gambia, Senegal, Nigeria, Ghana and Kenya go straight to local carrier routes. SMS reaches 30 more countries, and where it can’t land yet the API says so up front instead of accepting a message that won’t arrive.

+220 · +221 · +233 · +234 · +254 direct
SMS to 30 more countries
422 when SMS can’t land yet

+220+221+234+233+254

One-time passcodes, handled end to end

Send a code by SMS or email and verify it with one call. Wrong guesses are counted, the code locks after too many, and each number is rate-limited so nobody can farm your quota.

POST /v1/otp/send
POST /v1/otp/verify
5 attempts · expires in 5 minutes

Send a codeSMS or email

Verify the codeChecked server-side

Lock on retriesToo many wrong codes

Rate-limitPer phone number

otp.verifiedSent to your stack

Broadcasts you can account for

Drop in a CSV, schedule it, and follow every recipient from queued to accepted to delivered, as carriers confirm it. Duplicates are merged, unsubscribed emails are skipped, and failures come back with the carrier’s reason attached.

POST /v1/broadcast
GET /v1/broadcast/:id
One status per recipient

Upload a CSV

Validate numbers

Merge duplicates

Send at 09:00

Track each recipient

Tobaski promo

SMS

Scheduled · Fri 09:00

5,000 recipients12 duplicates

Delivered4,812 / 5,000

Top failureAbsent subscriber · 38

Signed webhooks back to your stack

Every event is signed with HMAC-SHA256 so you can prove it came from us, carries an id you can dedupe on, and is retried with exponential backoff, up to five attempts, if your endpoint is down.

HMAC-SHA256 signature
Event id to dedupe on
5 attempts, exponential backoff

Event

HMAC-SHA256

otp.sent200 · 84ms

otp.verified200 · 142ms

broadcast.queuedRetry 2 → 200

Coverage

Where your messages go today

Every number is routed by country. SMS goes out wherever it lands today. Where it can’t yet, the API says so up front instead of accepting a message that won’t arrive — send those on the email channel.