One API for calls, SMS, and AI — built for modern teams.
Ringflow's REST API gives you programmatic control over every part of your communications stack — outbound calls, bulk SMS, dual-channel recordings, AI Receptionist agents, and real-time event webhooks — all behind a single authenticated endpoint.
curl -X POST https://api.ringflow.com/v2/calls \
-H "Authorization: Bearer $RINGFLOW_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"to": "+14155550199",
"from": "+19172544289",
"recordDualChannel": true,
"aiReceptionistId": "agent_rfw_support"
}'
# 201 Created
{
"id": "call_rfw_2Kj8mNpQ",
"status": "ringing",
"to": "+14155550199",
"recording": true,
"ai": true
}Everything you need, nothing you don't.
Six resource groups, one base URL, one authentication scheme. Every endpoint is versioned, returns consistent JSON, and ships with request/response examples in the full reference.
- POST/v2/calls— Place outbound call to any number
- GET/v2/calls/:id— Fetch live status, duration & recording
- POST/v2/calls/:id/transfer— Warm or cold transfer mid-call
- DELETE/v2/calls/:id— Terminate an active call immediately
- POST/v2/messages— Send SMS or MMS to a single recipient
- POST/v2/messages/bulk— Batch up to 1 000 messages per request
- GET/v2/messages/:id— Poll delivery status and carrier receipt
- POST/v2/calls/:id/record— Start dual-channel call recording
- DELETE/v2/calls/:id/record— Stop recording and trigger storage
- POST/v2/recordings/:id/transcribe— Request async AI transcription
- POST/v2/ai/agents— Provision a new AI Receptionist
- PUT/v2/ai/agents/:id/knowledge— Push FAQs, docs & escalation rules
- GET/v2/ai/sessions/:id/summary— Retrieve post-call AI summary
- POST/v2/events/subscriptions— Subscribe to any platform event
- GET/v2/events/subscriptions— List and filter your subscriptions
- DELETE/v2/events/subscriptions/:id— Remove an event subscription
- POST/v2/auth/tokens— Issue short-lived bearer token
- POST/v2/auth/keys— Create scoped workspace API key
- PUT/v2/auth/keys/:id/rotate— Zero-downtime key rotation
Idiomatic clients for your stack.
Every Ringflow SDK is built code-first — not generated from a spec. Retries, pagination cursors, and webhook verification are first-class, not afterthoughts.
import { Ringflow } from "@ringflow/sdk"
const client = new Ringflow({
apiKey: process.env.RINGFLOW_API_KEY,
region: "us-east-1",
})
// Place a call and stream status updates
const call = await client.calls.create({
to: "+14155550199",
from: "+19172544289",
recordDualChannel: true,
onStatus: (evt) => console.log(evt.status),
})
console.log(call.id) // call_rfw_2Kj8mNpQPredictable limits at every tier.
Limits are enforced per workspace, not per IP. Every response carries X-RateLimit-Remaining, X-RateLimit-Reset, and a Retry-After header on 429s so you can back off gracefully.
| Plan | Sustained | Burst cap | Concurrent calls |
|---|---|---|---|
| Sandbox | 5 req/s | 15 req/s | 2 calls |
| Starter | 40 req/s | 80 req/s | 25 calls |
| Business | 150 req/s | 300 req/s | 150 calls |
| EnterpriseCustom | Custom | Custom | Unlimited |
Built different. Priced fair.
Most telephony APIs bolt AI on as an afterthought. Ringflow built AI, voice, and messaging from the ground up as a single coherent API — so you don't duct-tape three vendors together.
| Capability | Ringflow | Typical alternative |
|---|---|---|
| Unified calling + SMS + AI in one API | ✕ | |
| Permanent sandbox — no expiry, no card | ✕ | |
| Dual-channel recording out of the box | ✕ | |
| AI Receptionist via REST endpoint | ✕ | |
| HMAC-signed webhook deliveries | ||
| Zero-downtime API key rotation | ✕ | |
| Enterprise security audit + BAA available | ✕ |
Our Commitment
A REST API built to production standards.
Ringflow's API is designed to handle real production workloads — consistent JSON responses, strong authentication, clear rate limit signalling, and a permanent sandbox for safe integration testing.
Loved by engineering teams across industries.
From healthcare to retail — Ringflow's API powers production communications at scale.
Arjun Mehta
Head of Engineering, Zenia Health — Mumbai
“Ringflow's API let us embed voice triage into our patient portal in two weeks. The AI Receptionist endpoint alone cut our after-hours call volume by 40%.”
Rachel Torres
VP of Product, ClearLane Finance — Austin TX
“We migrated three contact centre vendors onto Ringflow in one quarter. The unified REST surface made our integration straightforward — one auth flow, one webhook schema, everything.”
Ben Hargreaves
Platform Lead, StackRoute — London
“The dual-channel recording and async transcription endpoints saved us from building our own speech pipeline. Ringflow just handles it, and the latency is genuinely impressive.”
Nadia Yusupova
CTO, Orbis Retail — Dubai
“Our SMS bulk endpoint sends 50 000 order confirmations daily without a hiccup. Delivery receipts land in our webhook within seconds — exactly what retail ops demands.”
Tom Fitzgerald
Senior Backend Engineer, Lawbridge — Chicago IL
“Key rotation with zero downtime was the feature that sold our security team. Rolling API keys without a maintenance window is something our old provider simply couldn't do.”
Soo-Jin Park
Solutions Architect, Clearview SaaS — Seoul
“The Go SDK is idiomatic and compiles clean on every CI run. Context cancellation, retries, and rate-limit back-off work exactly the way you'd expect a first-class client to behave.”
FAQ
Frequently Asked Questions
Proactively answering FAQs boosts user confidence and cuts down on support tickets.
Voice, SMS, and AI — all wired up before lunch.
Free trial · No card · Free number porting · SLA-backed uptime