> ## Documentation Index > Fetch the complete documentation index at: https://docs.axle.energy/llms.txt > Use this file to discover all available pages before exploring further. # Enrol site > Enrol a site in a proposition. This is the commitment point — it activates the proposition for the site. Idempotent: if the site is already enrolled, returns `already_enrolled` without making changes. A 200 response always means the site is enrolled; `status` only distinguishes a new enrolment from an existing one. Any failure returns an HTTP error and leaves the site unenrolled, so fix the cause and call again. If the site previously withdrew from this proposition (for example via `/unenrol`), returns 422 with `detail.code` set to `previously_withdrew`. Set `override_withdrawal` to true to re-enrol; this is the recommended default for user-initiated re-enrolment. ## OpenAPI ````yaml POST /entities/site/{site_id}/enrol openapi: 3.1.0 info: title: Axle API Docs description: >- For full documentation please see our official docs at docs.axle.energy version: 1.4.6 servers: - url: https://api-sandbox.axle.energy security: [] tags: - name: 1. Authentication description: Authenticate yourself with the Axle API - name: 2. Meters description: Find key info about your sites - name: 3. Sites description: Register your sites with Axle; configure market participation - name: 4. Assets description: Register your assets with Axle - name: 5. Data description: Send asset metrics to Axle, for analysis and optimisation purposes - name: 6. Rewards description: >- Determine how much your users have earned by participating with Axle; allow balance withdrawal - name: 7. Validation description: Validate structured data against Axle's rules - name: 8. Examples description: Get example data for testing paths: /entities/site/{site_id}/enrol: post: tags: - 3. Sites summary: Enrol Site description: >- Enrol a site in a proposition. This is the commitment point — it activates the proposition for the site. Idempotent: if the site is already enrolled, returns `already_enrolled` without making changes. A 200 response always means the site is enrolled; `status` only distinguishes a new enrolment from an existing one. Any failure returns an HTTP error and leaves the site unenrolled, so fix the cause and call again. If the site previously withdrew from this proposition (for example via `/unenrol`), returns 422 with `detail.code` set to `previously_withdrew`. Set `override_withdrawal` to true to re-enrol; this is the recommended default for user-initiated re-enrolment. operationId: enrol_site_entities_site__site_id__enrol_post parameters: - name: site_id in: path required: true schema: type: string format: uuid title: Site Id requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/EnrolRequest' responses: '200': description: Successfully enrolled or already enrolled content: application/json: schema: $ref: '#/components/schemas/EnrolResponse' '400': description: Invalid request (e.g. missing boundary meter consent) content: application/json: schema: $ref: '#/components/schemas/ErrorWithDetail' '404': description: Site not found or not authorized content: application/json: schema: $ref: '#/components/schemas/ErrorWithDetail' '422': description: >- Enrolment refused. Either eligibility prerequisites are not met (`detail.eligibility` holds the per-site and per-asset breakdown) or the site previously withdrew from this proposition (`detail.code` is `previously_withdrew`; resend with `override_withdrawal: true`). content: application/json: schema: $ref: '#/components/schemas/EnrolRejectedResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorWithDetail' security: - OAuth2PasswordBearer: [] components: schemas: EnrolRequest: properties: proposition: type: string enum: - limited_pause - full_asset_schedule_control - price_curve title: Proposition description: Proposition to enrol for examples: - limited_pause override_withdrawal: type: boolean title: Override Withdrawal description: >- Set to true to re-enrol regardless of previous withdrawals. If this is a user-initated action, overriding previous withdrawals is recommended. default: false examples: - false gave_boundary_meter_consent_at: type: string format: date-time title: Gave Boundary Meter Consent At description: >- Optional timezone-aware ISO 8601 timestamp recording when the household gave boundary meter consent. If provided, overwrites any existing meter consent timestamp on the site. type: object required: - proposition title: EnrolRequest description: Request model for enrolling a site in a proposition. EnrolResponse: properties: site_id: type: string format: uuid title: Site Id description: ID of the enrolled site examples: - a1b2c3d4-e5f6-7890-abcd-ef1234567890 status: type: string enum: - enrolled - already_enrolled title: Status description: >- Outcome of the enrolment attempt. Both `enrolled` and `already_enrolled` indicate success. examples: - enrolled type: object required: - site_id - status title: EnrolResponse description: Outcome of an enrolment attempt. ErrorWithDetail: properties: detail: type: string title: Detail type: object required: - detail title: ErrorWithDetail description: Standard error response with a detailed message. EnrolRejectedResponse: properties: detail: $ref: '#/components/schemas/EnrolRejectedDetail' type: object required: - detail title: EnrolRejectedResponse description: 422 body returned when an enrolment is refused. Nothing is persisted. EnrolRejectedDetail: properties: message: type: string title: Message description: Human-readable reason the enrolment was refused examples: - 'Prerequisites not met for proposition: limited_pause' code: type: string const: previously_withdrew title: Code description: >- Set when the site previously withdrew from this proposition. Resend with `override_withdrawal: true` to re-enrol. eligibility: allOf: - $ref: '#/components/schemas/SiteEligibilityDetail' description: >- Set when eligibility prerequisites are not met: the per-site and per-asset breakdown. type: object required: - message title: EnrolRejectedDetail description: >- Why an enrolment was refused: `code` for a prior withdrawal, `eligibility` for unmet prerequisites. SiteEligibilityDetail: properties: eligible_propositions: items: type: string enum: - limited_pause - full_asset_schedule_control - price_curve type: array title: Eligible Propositions default: [] site_id: type: string format: uuid title: Site Id examples: - a1b2c3d4-e5f6-7890-abcd-ef1234567890 site_properties: allOf: - $ref: '#/components/schemas/SiteProperties' examples: - has_meter_consent: true is_half_hourly_settled: false assets: items: $ref: '#/components/schemas/AssetEligibilityDetail' type: array title: Assets default: [] type: object required: - site_id - site_properties title: SiteEligibilityDetail description: Eligibility detail for a site's proposition eligibility check. SiteProperties: properties: is_half_hourly_settled: type: boolean title: Is Half Hourly Settled has_meter_consent: type: boolean title: Has Meter Consent type: object required: - is_half_hourly_settled - has_meter_consent title: SiteProperties description: Site-level properties relevant to eligibility evaluation. AssetEligibilityDetail: properties: asset_id: type: string format: uuid title: Asset Id examples: - b2c3d4e5-f6a7-8901-bcde-f23456789012 external_id: type: string title: External Id examples: - charger-001 propositions: items: $ref: '#/components/schemas/PropositionEligibility' type: array title: Propositions default: [] type: object required: - asset_id - external_id title: AssetEligibilityDetail description: Eligibility detail for a single asset across all propositions. PropositionEligibility: properties: proposition: type: string enum: - limited_pause - full_asset_schedule_control - price_curve title: Proposition examples: - limited_pause is_eligible: type: boolean title: Is Eligible issues: items: $ref: '#/components/schemas/EligibilityCode' type: array title: Issues default: [] type: object required: - proposition - is_eligible title: PropositionEligibility description: Eligibility detail for a single proposition. EligibilityCode: type: string enum: - asset_model_not_set - asset_model_not_found - asset_model_not_cop11_qualified - asset_installation_date_not_set - asset_model_enrol_eligibility_override - non_domestic_site - mpan_not_set - meter_id_not_set - meter_id_not_found - postcode_not_in_eligible_area title: EligibilityCode description: Codes identifying specific eligibility issues for an asset. securitySchemes: OAuth2PasswordBearer: type: oauth2 flows: password: scopes: {} tokenUrl: auth/token-form ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.