> ## Documentation Index > Fetch the complete documentation index at: https://docs.tilt.now/llms.txt > Use this file to discover all available pages before exploring further. # Create Account Backtest > Start a new backtest job for a client ## OpenAPI ````yaml POST /api/v1/custom/org/{organization_uuid}/clients/{client_uuid}/accounts/{account_uuid}/backtests/ openapi: 3.0.3 info: title: TILT version: 0.0.1 servers: [] security: [] paths: /api/v1/custom/org/{organization_uuid}/clients/{client_uuid}/accounts/{account_uuid}/backtests/: post: tags: - api description: Start a new backtest job for a client operationId: api_v1_custom_org_clients_accounts_backtests_create parameters: - in: path name: account_uuid schema: type: string format: uuid required: true - in: path name: client_uuid schema: type: string format: uuid required: true - in: path name: organization_uuid schema: type: string format: uuid required: true requestBody: content: application/json: schema: $ref: '#/components/schemas/StartBacktestRequest' application/x-www-form-urlencoded: schema: $ref: '#/components/schemas/StartBacktestRequest' multipart/form-data: schema: $ref: '#/components/schemas/StartBacktestRequest' responses: '202': content: application/json: schema: $ref: '#/components/schemas/CustomizationBacktestJob' description: '' security: - ProAPIToken: [] components: schemas: StartBacktestRequest: type: object properties: start_date: type: string format: date end_date: type: string format: date rebalance_period: allOf: - $ref: '#/components/schemas/StartBacktestRequestRebalancePeriodEnum' default: MONTHLY tax_gamma: type: number format: double maximum: 100 minimum: 0 tax_loss_threshold_bps: type: number format: double maximum: 5000 minimum: 0 starting_nav: type: number format: double maximum: 1000000000 minimum: 100 ls_tlh_factor: $ref: '#/components/schemas/LsTlhFactorEnum' diversify: $ref: '#/components/schemas/DiversifyBacktestRequest' CustomizationBacktestJob: type: object properties: id: type: string format: uuid readOnly: true status: allOf: - $ref: '#/components/schemas/ScenarioAnalysisJobStatusEnum' readOnly: true params: allOf: - $ref: '#/components/schemas/StartBacktestRequest' readOnly: true nullable: true resolved_params: allOf: - $ref: '#/components/schemas/BacktestResolvedParams' nullable: true readOnly: true progress: allOf: - $ref: '#/components/schemas/BacktestProgress' nullable: true readOnly: true result: type: object additionalProperties: $ref: '#/components/schemas/BacktestCaseResult' description: Dictionary mapping case names to case results readOnly: true error_message: type: string readOnly: true nullable: true created_at: type: string format: date-time readOnly: true started_at: type: string format: date-time readOnly: true nullable: true finished_at: type: string format: date-time readOnly: true nullable: true required: - created_at - error_message - finished_at - id - params - progress - resolved_params - result - started_at - status StartBacktestRequestRebalancePeriodEnum: enum: - MONTHLY type: string description: '* `MONTHLY` - MONTHLY' LsTlhFactorEnum: enum: - quality - value - growth type: string description: |- * `quality` - quality * `value` - value * `growth` - growth DiversifyBacktestRequest: type: object properties: tilt_asset_id: type: string description: Tilt asset ID of the concentrated ticker. basis_fraction: type: number format: double maximum: 1 minimum: 0 description: >- Cost basis as a fraction of the initial quote, from 0 to 1. For example, 0.25 means 25%. acquisition_date: type: string format: date description: Date the concentrated position was acquired (YYYY-MM-DD). tier: allOf: - $ref: '#/components/schemas/TierEnum' description: >- Long/short exposure: 140% long and 40% short, or 200% long and 100% short. * `140/40` - 140/40 * `200/100` - 200/100 monthly_tax_budget: type: number format: double minimum: 0 description: >- Monthly tax budget in USD, applied when trades are selected, before later wash-sale amendments. required: - acquisition_date - basis_fraction - monthly_tax_budget - tier - tilt_asset_id ScenarioAnalysisJobStatusEnum: enum: - PENDING - RUNNING - SUCCESS - FAILURE type: string description: |- * `PENDING` - PENDING * `RUNNING` - RUNNING * `SUCCESS` - SUCCESS * `FAILURE` - FAILURE BacktestResolvedParams: type: object properties: start_date: type: string format: date end_date: type: string format: date rebalance_period: $ref: '#/components/schemas/BacktestResolvedParamsRebalancePeriodEnum' starting_nav: type: number format: double tax_gamma: type: number format: double nullable: true tax_loss_threshold_bps: type: number format: double nullable: true diversify: $ref: '#/components/schemas/DiversifyBacktestRequest' required: - end_date - rebalance_period - start_date - starting_nav - tax_gamma - tax_loss_threshold_bps BacktestProgress: type: object properties: planned_periods: type: integer completed_periods: type: integer last_completed_period: type: string format: date nullable: true last_progress_at: type: string format: date-time nullable: true required: - completed_periods - last_completed_period - last_progress_at - planned_periods BacktestCaseResult: type: object description: Serializer for a single case's backtest results. properties: run_evidence: type: object additionalProperties: {} description: >- Recorded run: schema (1), build (release, engine_version), initialization (kind, starting_nav), window (requested_start, requested_end, first_solve_date, last_solve_date, last_nav_date), periods (date, risk_model_snapshot, effective_tax_gamma, effective_tax_loss_threshold_bps, effective_short_term_tax_rate, effective_long_term_tax_rate, tax_budget_selected_gamma), tax_gamma (requested, differing_dates, not_captured_dates). Tax rates are decimal fractions from each period's response config report. Uncaptured values are null. Older runs may lack the tax rate fields. complete: type: boolean backtest_dispositions: type: array items: type: object additionalProperties: {} input_provenance: type: array items: type: object additionalProperties: {} recovery_receipts: type: array items: type: object additionalProperties: {} diversify_months: type: array items: $ref: '#/components/schemas/DiversifyBacktestMonth' diversify_summary: $ref: '#/components/schemas/DiversifyBacktestSummary' diversify_initialization: type: object additionalProperties: {} description: >- Measured initial quote and cost basis per share in USD, shares, and starting NAV in USD. summaries: type: object additionalProperties: type: object additionalProperties: type: number format: double nullable: true description: Dictionary mapping quantity names to date-to-value mappings tax_summaries: type: object additionalProperties: type: object additionalProperties: type: number format: double nullable: true description: Dictionary mapping quantity names to date-to-value mappings assets: type: array items: $ref: '#/components/schemas/BacktestAsset' nullable: true index_period_return: type: object additionalProperties: type: number format: double description: >- Account index return per period as a decimal fraction (0.01 = 1%), weighted by the engine's benchmark weights using prior NYSE closing prices, aligned with the portfolio. Keys are period-start rebalance dates (yyyy-mm-dd), covering the next rebalance or final valuation date. Absent from older saved runs. benchmark_period_return: type: object additionalProperties: type: number format: double description: >- Account benchmark return per period as a decimal fraction (0.01 = 1%), weighted by the engine's benchmark weights on the same prices as the portfolio. Keys are period-start rebalance dates (yyyy-mm-dd), covering the next rebalance or final valuation date. No entry without a following valuation. Absent from older saved runs. comparison_index_returns: type: object additionalProperties: type: string format: decimal pattern: ^-?\d{0,5}(?:\.\d{0,10})?$ nullable: true description: >- Dictionary mapping dates (yyyy-mm-dd) to the return values of a reference index. TierEnum: enum: - 140/40 - 200/100 type: string description: |- * `140/40` - 140/40 * `200/100` - 200/100 BacktestResolvedParamsRebalancePeriodEnum: enum: - MONTHLY - WEEKLY type: string description: |- * `MONTHLY` - MONTHLY * `WEEKLY` - WEEKLY DiversifyBacktestMonth: type: object properties: month_index: type: integer description: Month number, starting at 0 for the formation month. date: type: string format: date status: $ref: '#/components/schemas/DiversifyBacktestMonthStatusEnum' concentrated_weight: type: number format: double description: Concentrated position weight as a fraction; 0.10 means 10%. concentrated_shares: type: number format: double description: Shares remaining in the concentrated position. active_risk_pct: type: number format: double description: Model-implied annualized tracking error in percent; 4 means 4%. period_tax_due: type: number format: double description: Tax due in USD when this month's trades were selected. tax_due: type: number format: double description: Tax due in USD after later wash-sale amendments. complete: type: boolean description: Tracking error is below 4% and concentrated weight is at most 10%. candidate_solver_time_seconds: type: number format: double description: Time spent solving candidates, in seconds. month_elapsed_seconds: type: number format: double description: Total time spent processing the month, in seconds. audit: type: object additionalProperties: {} description: Recorded monthly selection details. source_run_id: type: string predecessor_run_id: type: string nullable: true required: - active_risk_pct - audit - candidate_solver_time_seconds - complete - concentrated_shares - concentrated_weight - date - month_elapsed_seconds - month_index - period_tax_due - status - tax_due DiversifyBacktestSummary: type: object properties: first_te_below_4_month: type: integer nullable: true description: >- First month with tracking error below 4%; formation is month 0. Null if never reached. years_to_te_below_4: type: number format: double nullable: true description: >- First month with tracking error below 4%, divided by 12. Null if never reached. first_weight_at_most_10_month: type: integer nullable: true description: >- First month with concentrated weight at most 10%; formation is month 0. Null if never reached. complete: type: boolean description: Tracking error is below 4% and concentrated weight is at most 10%. required: - complete - first_te_below_4_month - first_weight_at_most_10_month - years_to_te_below_4 BacktestAsset: type: object description: Serializer for individual asset entries in backtest results. properties: symbol: type: string TILT_ASSET_ID: type: string nullable: true optimized_weight: type: object additionalProperties: type: number format: double nullable: true benchmark_weight: type: object additionalProperties: type: number format: double nullable: true unrealized_pnl_gain: type: object additionalProperties: type: number format: double nullable: true unrealized_pnl_loss: type: object additionalProperties: type: number format: double nullable: true wash_sale_aware_loss: type: object additionalProperties: type: number format: double nullable: true required: - symbol DiversifyBacktestMonthStatusEnum: enum: - accepted - held type: string description: |- * `accepted` - accepted * `held` - held securitySchemes: ProAPIToken: type: apiKey in: header name: X-Api-Key ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.