> ## Documentation Index > Fetch the complete documentation index at: https://docs-test.symmetry.com/llms.txt > Use this file to discover all available pages before exploring further. # Compare two paychecks and explain the differences > Accepts two PayCalc contexts. Runs both through STE, computes a structured diff, and returns a single AI-generated narrative explaining only the meaningful differences. ## OpenAPI ````yaml /ste/api-reference/stl-api.yaml post /v1/experimental/compare openapi: 3.1.0 info: title: Symmetry Tax Logic API description: >- NOTE: All `/v1/*` endpoints require a Bearer token. **To authenticate:** call `GET /authentication/login` on the Symmetry API with your API key in the `api-key` header, then use the returned `accessToken` as the Bearer token below. contact: name: Symmetry Software url: https://www.symmetry.com/ email: support@symmetry.com license: name: Terms of Use url: https://www.symmetry.com/terms version: 2026.7.1 servers: - url: https://api.symmetry.com/stl security: - BearerAuth: [] tags: - name: Symmetry Tax Logic description: >- Generate AI-powered tax calculation explanations using the Symmetry Tax Engine paths: /v1/experimental/compare: post: tags: - Symmetry Tax Logic summary: Compare two paychecks and explain the differences description: >- Accepts two PayCalc contexts. Runs both through STE, computes a structured diff, and returns a single AI-generated narrative explaining only the meaningful differences. operationId: compare_v1_experimental_v1_experimental_compare_post requestBody: content: application/json: schema: $ref: '#/components/schemas/CompareInput' required: true responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/CompareOutput' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: CompareInput: properties: taxIds: anyOf: - type: string - items: type: string type: array title: Taxids description: >- Tax ID(s) to compare. String for single tax, array for multiple (max 10) context_a: $ref: '#/components/schemas/PayCalcContext' description: First paycheck (earlier payDate becomes 'before') context_b: $ref: '#/components/schemas/PayCalcContext' description: Second paycheck (later payDate becomes 'after') type: object required: - taxIds - context_a - context_b title: CompareInput description: >- Input for POST /v1/experimental/compare — two PayCalc contexts with 1-10 tax IDs. examples: - context_a: payCalc: employeeID: emp1 payrollRunParameters: payDate: '2026-01-01' payPeriodNumber: 1 payPeriodsPerYear: 52 taxJurisdictionParms: - uniqueTaxID: 00-000-0000-FIT-000 wages: [] context_b: payCalc: employeeID: emp1 payrollRunParameters: payDate: '2026-01-08' payPeriodNumber: 2 payPeriodsPerYear: 52 taxJurisdictionParms: - uniqueTaxID: 00-000-0000-FIT-000 wages: [] taxIds: 00-000-0000-FIT-000 - context_a: payCalc: employeeID: emp1 payrollRunParameters: payDate: '2026-01-01' payPeriodNumber: 1 payPeriodsPerYear: 52 taxJurisdictionParms: - uniqueTaxID: 00-000-0000-FIT-000 wages: [] context_b: payCalc: employeeID: emp1 payrollRunParameters: payDate: '2026-01-08' payPeriodNumber: 2 payPeriodsPerYear: 52 taxJurisdictionParms: - uniqueTaxID: 00-000-0000-FIT-000 wages: [] taxIds: - 00-000-0000-FIT-000 - 00-000-0000-FICA-000 CompareOutput: properties: id: type: string title: Id description: Request ID (ULID) summary: type: string title: Summary description: Single flowing narrative explaining differences (≤200 words) paycheck: $ref: '#/components/schemas/Paycheck' description: Paycheck-level diff section (gross, net, wages, benefits) results: items: $ref: '#/components/schemas/TaxResult' type: array title: Results description: >- Per-tax comparison results — one entry per requested tax that resolved in at least one context usage: anyOf: - $ref: '#/components/schemas/TokenUsage' - type: 'null' description: >- Token usage statistics from the Bedrock call (None if the call did not complete) ai_disclosure: type: string title: Ai Disclosure description: Static AI-generated content disclaimer for client display default: >- This explanation is generated using AI and is provided for informational purposes only. It does not constitute tax, legal, or financial advice. AI can make mistakes. type: object required: - id - summary - paycheck title: CompareOutput description: Response for POST /v1/experimental/compare. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError PayCalcContext: properties: payCalc: anyOf: - additionalProperties: true type: object - type: 'null' title: Paycalc description: >- Single employee PayCalc object (flat structure - no PayCalcRequest wrapper) session: anyOf: - type: string - type: 'null' title: Session description: Base64-encoded STE session string type: object title: PayCalcContext description: |- Context containing a single employee's payCalc data OR a session string. Provide exactly one of payCalc or session. Paycheck: properties: gross_a: type: number title: Gross A description: Gross on the 'before' paycheck gross_b: type: number title: Gross B description: Gross on the 'after' paycheck gross_delta: type: number title: Gross Delta description: gross_b - gross_a net_a: type: number title: Net A description: Net (take-home) on the 'before' paycheck net_b: type: number title: Net B description: Net (take-home) on the 'after' paycheck net_delta: type: number title: Net Delta description: net_b - net_a pay_frequency_changed: type: boolean title: Pay Frequency Changed description: True when payPeriodsPerYear differs between the two paychecks default: false jurisdiction_changed: type: boolean title: Jurisdiction Changed description: >- True when at least one location code differs between the two paychecks default: false wage_differences: items: $ref: '#/components/schemas/ItemDelta' type: array title: Wage Differences benefit_differences: items: $ref: '#/components/schemas/ItemDelta' type: array title: Benefit Differences type: object required: - gross_a - gross_b - gross_delta - net_a - net_b - net_delta title: Paycheck description: >- Paycheck-level diff section (gross/net plus item-level wage and benefit deltas). TaxResult: properties: taxId: type: string title: Taxid description: The uniqueTaxID this result is for amount_a: anyOf: - type: number - type: 'null' title: Amount A description: Tax amount on the 'before' paycheck amount_b: anyOf: - type: number - type: 'null' title: Amount B description: Tax amount on the 'after' paycheck delta: anyOf: - type: number - type: 'null' title: Delta description: amount_b - amount_a category: anyOf: - $ref: '#/components/schemas/DifferenceCategory' - type: 'null' note: anyOf: - type: string - type: 'null' title: Note description: Machine-readable cue describing the cause error: anyOf: - type: string - type: 'null' title: Error description: Error message if this tax could not be compared type: object required: - taxId title: TaxResult description: >- Per-tax comparison result. Either populated with diff fields, or with `error` for per-tax failures. TokenUsage: properties: input_tokens: type: integer title: Input Tokens description: Number of input tokens sent to the model output_tokens: type: integer title: Output Tokens description: Number of output tokens generated by the model type: object required: - input_tokens - output_tokens title: TokenUsage description: Token usage statistics from the LLM invocation. ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type type: object required: - loc - msg - type title: ValidationError ItemDelta: properties: label: type: string title: Label description: Human-readable label (e.g., 'Federal Income Tax') id: type: string title: Id description: >- Prefixed stable identifier: 'wage:' for wages, 'benefit:' for benefits, raw tax-id for taxes. amount_a: type: number title: Amount A description: Amount from the 'before' paycheck amount_b: type: number title: Amount B description: Amount from the 'after' paycheck delta: type: number title: Delta description: amount_b - amount_a category: $ref: '#/components/schemas/DifferenceCategory' description: Classification bucket note: anyOf: - type: string - type: 'null' title: Note description: >- Machine-readable cue describing the cause (e.g., 'tax_introduced', 'rate_increase', 'wage_base_reset'). type: object required: - label - id - amount_a - amount_b - delta - category title: ItemDelta description: A single surfaced difference between two paychecks. DifferenceCategory: type: string enum: - wage_base_tax_limit - income_bracket_change - wage_amount_change - non_standard_wages - benefits_change - jurisdiction_change - new_tax - exemption_change - withholding_config_change - pay_frequency_change - tax_year_rollover - rate_update title: DifferenceCategory description: Classification bucket for a paycheck delta. securitySchemes: BearerAuth: type: http scheme: bearer description: >- Obtain a token by calling GET /authentication/login with your Symmetry API key in the api-key header. Paste the accessToken value here. ````