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These APIs are maintained for long-term support only. New integrations should use the InteractSMS API v2, which offers OAuth 2.0 authentication, campaign naming, scheduling, and improved error handling.
The v1 APIs are available at https://secure.interactsms.com/api/v1 and use basic credential authentication (username and password passed directly in the request body).

Available legacy APIs

JSON API (v1)

Send SMS via a JSON request body. Credentials passed as User and Password fields.

URL-Encoded API (v1)

Send SMS via application/x-www-form-urlencoded. Compatible with query-string integrations.

Key differences vs v2

Featurev1 (Legacy)v2 (Current)
AuthCredentials in bodyOAuth 2.0 JWT
Bulk sendSingle recipientMultiple recipients
SchedulingUnix timestampISO 8601 datetime
Campaign trackingNotifyId onlycampaignName + notifyId
Response formatPlain text / status stringStructured JSON
Last modified on April 8, 2026