Ship phone + SMS without a telecom team.
A softphone API for startups: one REST API, HMAC-signed webhooks and an MCP server — on top of a real VanceTel softphone. Stand up calling and texting in an afternoon instead of a quarter.
curl https://api.netexem.com/v1/messages \
-H "Authorization: Bearer $NETEXEM_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"from": "+15551234567",
"to": "+15557654321",
"body": "Thanks for signing up — reply STOP to opt out."
}'Your first text — sent before lunch.
The phone layer, already built.
A lean team should not spend a quarter wiring carriers, SIP and a dialer. VanceTel gives you the programmable pieces and the finished app together.
One REST API for SMS & calls
Send and receive two-way SMS and MMS, and place click-to-call, from a single REST endpoint. No carrier contracts, no SIP stack — one bearer token and you are sending.
Learn moreHMAC-signed webhooks
Subscribe once to inbound messages, delivery receipts and call events. Every payload is HMAC-SHA256 signed, so your endpoint can trust the event without extra plumbing.
Learn moreMCP server for your agents
A Model Context Protocol server lets agents and Claude Code act on your phone system in the loop — send a text, resolve a contact, check a message's status — without a custom integration.
Learn moreA finished app on top
You get a real softphone on iPhone, iPad, Mac, Apple Vision Pro, desktop and web. Your team uses the app while your code drives the API — no app to build yourself.
Learn moreSend a message, then listen for replies.
POST to send. Subscribe a webhook to receive. That is the whole integration — VanceTel runs the numbers, carriers and the softphone your team answers from.
- No SIP, carrier contracts or number provisioning to build
- Inbound replies and call events arrive as signed webhooks
- Every message also lands in the softphone shared inbox
curl https://api.netexem.com/v1/webhook_endpoints \
-H "Authorization: Bearer $NETEXEM_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"url": "https://yourapp.com/hooks/netexem",
"events": ["message.received", "message.delivered", "call.completed"]
}'
# Inbound events arrive HMAC-SHA256 signed — verify, then 200 OK.From signup to support, on the same numbers.
Onboarding flows that text
Fire a welcome text or a verification message from your signup handler. One POST, and it also lands in the softphone shared inbox for your team to follow.
Product notifications by SMS
Drive transactional alerts — confirmations, reminders, status changes — straight from your backend. Delivery receipts come back as webhooks you can log.
Talk to customers without a call center
Inbound texts and calls ring a real softphone on every device. Your founding team answers from their phone or laptop — no separate support tool to stand up.
Founder questions, answered.
Want to see the API and the softphone working together? Book a walkthrough.
How fast can a startup ship phone and SMS?
You can send your first text the same afternoon. Authenticate with a bearer token, POST to the messages endpoint with a from-number, a destination and a body, then subscribe a webhook for replies. VanceTel handles the carrier and number plumbing, so there is no telecom buildout before you ship.
Do we need to build a phone app ourselves?
No. VanceTel ships a finished softphone on iPhone, iPad, Mac, Apple Vision Pro, Windows/Mac desktop and the web. Your code drives the REST API and webhooks while your team uses the real app — you are not rebuilding a dialer or an inbox.
What can the API actually do?
The public API is write-and-event oriented: send and receive SMS/MMS, place click-to-call and pre-addressed text deep links, create and sync contacts, and subscribe to webhooks for inbound messages, delivery receipts and call events. The softphone app surfaces all of it in real time.
Is there an MCP server for AI agents?
Yes. VanceTel ships a Model Context Protocol server so agents and Claude Code can act on your phone system in the loop — send a text, look up a contact, check a message's status — alongside the REST API and webhooks.
Will it scale past the prototype?
The same REST API and HMAC-signed webhooks back both your first integration and production traffic. Messages flow over dedicated business numbers with TCPA opt-out handled automatically, so the path from prototype to launch does not require re-platforming.
Add phone + SMS to your product this week.
One REST API, signed webhooks and an MCP server — with a real VanceTel softphone on top. Ship without becoming a telecom team.