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Messaging & OTP

Transactional SMS API

POST /api/v1/communication/transactional-sms

The Transactional SMS from JustSwitch lets product teams integrate SMS messages in real time through a single REST integration. Designed for the SMS / WhatsApp lane, it removes manual checks, reduces drop-offs in onboarding funnels, and returns structured JSON that your risk engine, CRM, or core banking system can consume instantly.

  • Real-time integrate for SMS messages with sub-300ms median latency
  • Production-grade REST JSON with sandbox & webhook support
  • UIDAI / NPCI / MCA aligned partner routing where applicable
  • Audit logs, idempotency keys & enterprise SLA on JustSwitch
Get API keys Developer docs
Latency
< 300 ms
Uptime SLA
99.9%
Format
REST / JSON
Sandbox
Included

What is Transactional SMS?

The Transactional SMS from JustSwitch lets product teams integrate SMS messages in real time through a single REST integration. Designed for the SMS / WhatsApp lane, it removes manual checks, reduces drop-offs in onboarding funnels, and returns structured JSON that your risk engine, CRM, or core banking system can consume instantly.

Every request is authenticated with API keys, logged for audit, and routed through regulated partner rails where required. Responses follow a consistent `{ ok, data, message }` envelope so you can ship once and reuse the same error-handling patterns across all JustSwitch endpoints.

Whether you run a lending app, payment aggregator, or enterprise ERP, Transactional SMS scales horizontally with rate limits tuned for burst traffic during campaigns.

Developers choose JustSwitch for Transactional SMS because we aggregate multiple upstream providers behind one contract, one wallet settlement, and one support desk — so you launch faster while your compliance team retains full audit visibility through dashboard logs and exportable reports.

Fintech Enterprises SaaS System integrators

Technical specification

Endpoint details for Transactional SMS integration on JustSwitch.

POST /api/v1/communication/transactional-sms
Protocol HTTPS REST / JSON
Authentication Bearer API Key + IP allow-list
Sandbox Available — no live debits
Median latency < 300 ms
Rate limits Burst-friendly — contact for enterprise tiers
Webhooks Optional async notify
Idempotency reference_id recommended
API slug transactional-sms

Request parameters

reference_id string required

Your unique transaction or session reference for reconciliation

consent boolean required

User consent flag — required for regulated KYC / verification flows

input string required

Primary identifier for SMS messages

Response fields

status string

success | pending | failed

reference_id string

Echo of your request reference

verified_at datetime

ISO-8601 timestamp of completion

message string

Human-readable result or error detail

Key features

REST + JSON

HTTPS POST/GET with UTF-8 JSON bodies and predictable status codes.

Sandbox mode

Test end-to-end without debiting wallet or hitting live rails.

Webhooks

Async callbacks for pending states — payments, recharge, KYC, payouts.

Dashboard logs

Searchable request history with filters for support & audits.

Low latency

Median sub-300 ms for verification-class endpoints in production.

Enterprise SLA

99.9% uptime target with redundant routing and monitoring.

Who uses Transactional SMS?

Fi

Fintech startups

Ship SMS messages features in days, not quarters.

En

Enterprises

Replace legacy screen-scraping with compliant APIs.

Sa

SaaS platforms

Embed verification inside your vertical workflow.

Sy

System integrators

Standardise client deliveries on one aggregator.

How it works

  1. 01

    Obtain sandbox keys from the JustSwitch developer console.

  2. 02

    POST input identifiers; handle validation errors in-line.

  3. 03

    Map response fields into your workflow & go live with production keys.

Sample integration

Illustrative JSON for Transactional SMS — see developer docs for live schemas.

POST Request
{
    "input": "XXXXXXXX",
    "reference_id": "REQ-2026-001",
    "consent": true
}
200 Response
{
    "ok": true,
    "message": "Success",
    "data": {
        "status": "success",
        "reference_id": "JS-YFD822VO",
        "verified_at": "2026-06-23T22:47:53+00:00"
    }
}

Business benefits

  • Reduce manual ops cost by up to 70% on verification-heavy journeys
  • Improve conversion with inline validation instead of offline turnaround
  • Single contract & settlement across 200+ Indian fintech APIs
  • Audit-ready logs exported from the admin console
  • Dedicated solutions engineering for enterprise rollouts

Frequently asked questions

What is Transactional SMS used for?

It automates SMS / WhatsApp workflows so your application can verify or transact in real time without building direct integrations with multiple upstream providers.

How do I integrate Transactional SMS in my app?

Sign up on JustSwitch, obtain sandbox API keys, call the REST endpoint with JSON body, handle the unified response envelope, then switch to production keys after UAT sign-off.

How do I authenticate requests?

Use Bearer API keys from the JustSwitch dashboard. Sandbox and production keys are separated; rotate keys anytime without downtime.

Is there a sandbox for testing?

Yes — every API supports sandbox mode with simulated responses so engineering, QA, and compliance can sign off before go-live.

What about webhooks and async status?

Long-running operations (payments, recharge, some KYC steps) emit webhooks to your HTTPS endpoint with signed payloads for replay protection.

Is Transactional SMS compliant for regulated use in India?

JustSwitch routes requests through authorised AUA/KUA, NPCI, MCA and partner networks. Your legal team should map consent, data retention and licence obligations to your use case.

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Start building with Transactional SMS

Sandbox keys in minutes. Production access with compliance review for regulated endpoints.

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