> ## Documentation Index > Fetch the complete documentation index at: https://docs.orbit.devotel.io/llms.txt > Use this file to discover all available pages before exploring further. # Set a campaign's A/B variants > Configures multi-variant A/B testing on a campaign. Send a `variants` array (2–4 variants, each with a unique `variant_index` and a message body) to replace the variant set, and/or set the winner metric, holdout percentage, and multi-armed bandit toggle. All body fields are individually optional, but at least one must be present — a metric/holdout/bandit-only call updates those settings without touching the variant rows. Returns the resulting variant set. ## OpenAPI ````yaml /openapi.yaml post /api/v1/campaigns/{id}/variants openapi: 3.1.0 info: title: Devotel CPaaS API description: Orbit by Devotel — Communications Platform as a Service API version: 1.0.0 contact: name: Devotel url: https://devotel.io email: support@devotel.io license: name: Proprietary servers: - url: https://api.orbit.devotel.io description: Production security: - Bearer: [] - ApiKey: [] tags: - name: Messages description: >- Send and manage messages across all channels (SMS, WhatsApp, RCS, Email, Viber, etc.) - name: Fax description: >- List and track fax (MMS/T.38) transmissions on Telnyx-backed fax numbers (sending flows through the Messaging API) - name: Agents description: AI agent creation, configuration, and execution - name: Voice description: Voice calls, IVR, conferencing, and SIP trunking - name: OnCall description: On-call rotations and escalation policy planning for incident alerting - name: Webhooks description: Webhook endpoint management and delivery logs - name: Numbers description: Phone number search, provisioning, and configuration - name: Brand Identity description: >- Unified cross-channel brand trust posture (10DLC, toll-free, WhatsApp, RCS, branded calling, number KYC) - name: Contacts description: Contact management, segmentation, and lifecycle tracking - name: Campaigns description: Marketing campaign orchestration and analytics - name: Flows description: Automation flow builder and execution engine - name: Templates description: Message template management and approval workflows - name: Settings description: Organization, channel, and user preference settings - name: Verify description: OTP generation and verification across channels - name: Push description: Push notification delivery via FCM and APNs - name: Integrations description: Third-party service connections and OAuth management - name: CDP description: >- Customer Data Platform — activation surface (CRM object sync, streaming destinations, ad-audience activation) - name: Files description: >- Server-to-server media upload, listing, retrieval, and deletion (signed-URL backed) - name: Commerce description: >- Omnichannel conversational-commerce — persistent cart + checkout state machine, channel-agnostic hosted pay-by-link, native WhatsApp checkout, and AP2-style agent payment mandates. - name: Sync description: >- Real-time shared-state primitive (Twilio Sync parity) — Documents, Maps, Lists, and ephemeral Streams, with change events relayed over the /api/v1/ws/sync WebSocket gateway - name: Risk description: >- Unified cross-channel Trust & Fraud risk scoring — fuses SMS-pumping, URL-reputation, Verify Fraud Guard, and Voice Biometrics signals into one composite verdict queryable before a send or a call. - name: Orby description: >- In-dashboard Orby operator assistant: streamed assistant turns, conversation threads, product knowledge-base search, and the tool-action approval gate. Available to signed-in operators only (dashboard session auth — API-key requests are rejected). paths: /api/v1/campaigns/{id}/variants: post: tags: - Campaigns summary: Set a campaign's A/B variants description: >- Configures multi-variant A/B testing on a campaign. Send a `variants` array (2–4 variants, each with a unique `variant_index` and a message body) to replace the variant set, and/or set the winner metric, holdout percentage, and multi-armed bandit toggle. All body fields are individually optional, but at least one must be present — a metric/holdout/bandit-only call updates those settings without touching the variant rows. Returns the resulting variant set. parameters: - schema: type: string in: path name: id required: true requestBody: required: true content: application/json: schema: type: object properties: variants: type: array minItems: 2 maxItems: 4 description: >- Full replacement variant set. Each variant needs a unique variant_index. items: type: object required: - name - message_body - variant_index properties: id: type: string format: uuid description: Existing variant id. Omit to create a new variant. name: type: string maxLength: 120 message_body: type: string variant_index: type: integer minimum: 0 maximum: 3 description: >- Slot index (0–3). Must be unique across the variant set. ab_winner_metric: type: string enum: - delivered - opened - clicked - replied description: Metric used to pick the winning variant. ab_holdout_percent: type: integer minimum: 1 maximum: 50 description: >- Percentage of the audience withheld from all variants as a control group. ab_bandit: type: boolean description: >- Enable multi-armed bandit (Thompson) auto-optimization — traffic shifts toward leading variants mid-send instead of an even split. example: variants: - name: Variant A message_body: Flash sale — 20% off ends tonight. variant_index: 0 - name: Variant B message_body: 'Last chance: save 20% before midnight.' variant_index: 1 ab_winner_metric: clicked ab_holdout_percent: 10 responses: '200': description: The resulting variant set. content: application/json: schema: type: object properties: data: type: object properties: variants: type: array items: type: object properties: id: type: string name: type: string message_body: type: string variant_index: type: integer meta: $ref: '#/components/schemas/ResponseMeta' '404': description: Campaign not found. '422': description: >- Invalid variant payload (for example duplicate variant_index values, or no updatable field supplied). components: schemas: ResponseMeta: type: object required: - request_id - timestamp additionalProperties: false properties: request_id: type: string description: Unique request identifier (also returned as X-Request-Id header) timestamp: type: string format: date-time docs_url: type: string format: uri nullable: true securitySchemes: Bearer: type: http scheme: bearer bearerFormat: JWT description: Dashboard JWT token from Clerk ApiKey: type: apiKey name: X-API-Key in: header description: Server-to-server API key (dv_live_sk_*) ````