> ## Documentation Index > Fetch the complete documentation index at: https://docs.revilico.bio/llms.txt > Use this file to discover all available pages before exploring further. # Start a RevpKa run > Microscopic pKa of every acid and base site of one molecule: conformer-averaged free energies with a calibrated correction per site type. Starts a run and returns it with status `queued`; poll GET /v1/runs/{runId} until it finishes. Runs spend credits. **Limits:** `maxHeavyAtoms`: 60, `maxSmilesLength`: 2000, `minCharge`: -10, `maxCharge`: 10. How the engine works and how to read its results: [RevpKa documentation](/docs/revpka). **Scope:** `runs:write`. ## OpenAPI ````yaml /api-reference/openapi.json post /v1/engines/revpka/runs openapi: 3.1.0 info: title: Revilico API version: 1.0.0 description: >- Run Revilico's computational chemistry and biology engines from your own code: upload input files, start runs, follow them and read their results. servers: - url: https://public-api.revilico.bio security: - bearerAuth: [] tags: - name: Account description: Who you are, your credits and what your runs have used. - name: Engines description: The engines you can run, their parameter schemas and examples. - name: Files description: 'Upload input files: create an upload, then PUT the bytes.' - name: Runs description: Start, follow and cancel engine runs. - name: Results and outputs description: 'Read what a run produced: results, files and outputs.' - name: Projects description: Group runs into the projects you see in the web app. - name: Engine runs description: >- Start a run of one engine, with that engine's parameters and input files. Same endpoint as **Start a run**. - name: Health description: Service status. Needs no API key. paths: /v1/engines/revpka/runs: post: tags: - Engine runs summary: Start a RevpKa run description: >- Microscopic pKa of every acid and base site of one molecule: conformer-averaged free energies with a calibrated correction per site type. Starts a run and returns it with status `queued`; poll GET /v1/runs/{runId} until it finishes. Runs spend credits. **Limits:** `maxHeavyAtoms`: 60, `maxSmilesLength`: 2000, `minCharge`: -10, `maxCharge`: 10. How the engine works and how to read its results: [RevpKa documentation](/docs/revpka). **Scope:** `runs:write`. operationId: engineRuns.revpka requestBody: required: true content: application/json: schema: type: object properties: name: description: A name for the run, shown in the web app. type: string maxLength: 200 parameters: type: object properties: smiles: description: >- The molecule as one SMILES (up to 2000 characters, one component, no salts or spaces). Give either this or the structure input file. type: string minLength: 1 maxLength: 2000 charge: description: >- Total charge of the submitted form. Optional: the structure's own formal charges are used, and must agree when given. anyOf: - type: integer minimum: -10 maximum: 10 - type: 'null' settings: type: object properties: method: type: string enum: - g-xtb - aimnet2 description: >- Energy model. g-xtb (default; covers H-Rn, faster) or aimnet2 (neural network; H, B, C, N, O, F, Si, P, S, Cl, As, Se, Br, I only). Both are calibrated against measured pKa. mode: type: string enum: - careful - rapid - reckless description: >- Conformer depth: careful (default; up to 10 conformers per state), rapid (up to 3) or reckless (1). pka_window: type: array prefixItems: - type: number - type: number items: false minItems: 2 maxItems: 2 description: >- pKa range of interest, [low, high]; the default is [2, 12]. Sites screened outside it (plus buffer) are not computed. deprotonate_elements: type: array items: type: string pattern: ^[A-Za-z]{1,2}$ description: >- Elements whose atoms are tried as acid sites (symbols, case-insensitive); the default is ["N", "O", "S"]. protonate_elements: type: array items: type: string pattern: ^[A-Za-z]{1,2}$ description: >- Elements whose atoms are tried as base sites (symbols, case-insensitive); the default is ["N"]. deprotonate_atoms: type: array items: type: integer minimum: 1 maximum: 9007199254740991 description: >- 1-based atom indices to try as acid sites in addition to the element rules; the engine's default is none. protonate_atoms: type: array items: type: integer minimum: 1 maximum: 9007199254740991 description: >- 1-based atom indices to try as base sites in addition to the element rules; the engine's default is none. buffer: anyOf: - type: number minimum: 0 - type: 'null' description: >- pKa units beyond pka_window that a screened site may fall and still be computed; null (default) uses the mode’s own (10 for careful, 5 otherwise). additionalProperties: false description: >- Engine settings. Every key is optional; the engine fills absent ones with its defaults. additionalProperties: false inputs: type: object properties: structure: type: string description: >- One molecule (up to 60 heavy atoms): SDF or MOL recommended (they carry bonds and formal charges), or MOL2, PDB, XYZ, or a SMI file with one SMILES. One record only. Alternative to parameters.smiles. A file id (`file_…`). Formats: sdf, mol, mol2, pdb, xyz, smi; up to 10 MB. additionalProperties: false budget: description: Most credits the run may spend; it is stopped beyond that. type: number exclusiveMinimum: 0 projectId: description: >- Add the run to this project (`proj_…`); needs editor or owner on it. type: string additionalProperties: false examples: smiles-defaults: summary: >- Every acid and base site of niacin from a SMILES, with the engine defaults (g-xTB, careful). value: name: Niacin pKa parameters: smiles: OC(=O)c1cccnc1 inputs: {} file-narrow-window: summary: >- A structure file, physiological pKa range only, rapid mode, with one extra base site named by atom index. value: parameters: charge: 0 settings: mode: rapid pka_window: - 4 - 10 protonate_elements: - 'N' - O protonate_atoms: - 7 inputs: structure: file_… responses: '202': description: OK content: application/json: schema: $ref: '#/components/schemas/Run' '400': $ref: '#/components/responses/400' '401': $ref: '#/components/responses/401' '402': $ref: '#/components/responses/402' '403': $ref: '#/components/responses/403' '404': $ref: '#/components/responses/404' '422': $ref: '#/components/responses/422' '500': $ref: '#/components/responses/500' '502': $ref: '#/components/responses/502' components: schemas: Run: type: object properties: id: type: string description: Run id, `run_…`. engine: type: string description: Engine slug, e.g. `revredox`. name: type: - string - 'null' status: type: string enum: - queued - running - succeeded - failed - cancelled description: >- queued until the engine picks the run up; succeeded, failed and cancelled are final. statusReason: description: >- Why a cancelled run stopped: `user`, `insufficient_credits` or `budget_exceeded`. Null otherwise. type: - string - 'null' progress: type: number description: Progress the engine reports; 0 until it reports any. createdAt: type: string format: date-time startedAt: anyOf: - type: string format: date-time - type: 'null' endedAt: anyOf: - type: string format: date-time - type: 'null' budget: description: Most credits the run may spend, if one was set. type: - number - 'null' creditsUsed: type: number description: Credits charged to the run so far. error: anyOf: - type: object properties: message: type: string required: - message - type: 'null' description: Set when status is failed. links: type: object propertyNames: type: string additionalProperties: type: string description: 'Related endpoints: self, inputs, results, outputs, files.' warnings: description: >- Set when the run was created but a follow-up step, such as adding it to a project, failed. type: array items: type: string required: - id - engine - name - status - statusReason - progress - createdAt - startedAt - endedAt - budget - creditsUsed - error - links Error: type: object properties: error: type: object properties: code: type: string enum: - VALIDATION_FAILED - INVALID_ID - INVALID_PARAMETERS - INPUT_LIMIT_EXCEEDED - NOT_FOUND - FORBIDDEN - METHOD_NOT_ALLOWED - CONFLICT - PAYLOAD_TOO_LARGE - MISSING_CREDENTIALS - INVALID_CREDENTIALS - WRONG_ENVIRONMENT - CREDENTIALS_EXPIRED - CREDENTIALS_REVOKED - ACCOUNT_INACTIVE - API_ACCESS_NOT_ENABLED - INSUFFICIENT_SCOPE - SESSION_REQUIRED - TOO_MANY_AUTH_FAILURES - API_KEY_LIMIT_REACHED - ENGINE_NOT_ENABLED - DOCS_NOT_AVAILABLE - INSUFFICIENT_CREDITS - RUN_NOT_COMPLETE - ENGINE_SUBMIT_FAILED - RATE_LIMITED - SERVICE_UNAVAILABLE - INTERNAL_ERROR description: Stable within /v1; branch on this, not on the message. message: type: string description: Readable explanation, for people. details: description: >- Extra context, e.g. `issues` ({ path, message }[]) for validation errors. type: object propertyNames: type: string additionalProperties: {} required: - code - message required: - error responses: '400': description: >- The request is malformed. `error.code` is one of `VALIDATION_FAILED`, `INVALID_ID`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: VALIDATION_FAILED message: The request is malformed. '401': description: >- The API key is missing or not valid. `error.code` is one of `MISSING_CREDENTIALS`, `INVALID_CREDENTIALS`, `WRONG_ENVIRONMENT`, `CREDENTIALS_EXPIRED`, `CREDENTIALS_REVOKED`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: MISSING_CREDENTIALS message: The API key is missing or not valid. '402': description: >- Your organization doesn't have enough credits. `error.code` is one of `INSUFFICIENT_CREDITS`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: INSUFFICIENT_CREDITS message: Your organization doesn't have enough credits. '403': description: >- The key may not do this. `error.code` is one of `INSUFFICIENT_SCOPE`, `API_ACCESS_NOT_ENABLED`, `ENGINE_NOT_ENABLED`, `ACCOUNT_INACTIVE`, `FORBIDDEN`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: INSUFFICIENT_SCOPE message: The key may not do this. '404': description: Not found, or not visible to you. `error.code` is one of `NOT_FOUND`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: NOT_FOUND message: Not found, or not visible to you. '422': description: >- The parameters or input files don't fit the engine. `error.code` is one of `INVALID_PARAMETERS`, `INPUT_LIMIT_EXCEEDED`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: INVALID_PARAMETERS message: The parameters or input files don't fit the engine. '500': description: >- Something went wrong on our side. `error.code` is one of `INTERNAL_ERROR`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: INTERNAL_ERROR message: Something went wrong on our side. '502': description: >- The engine service rejected or failed the request. `error.code` is one of `ENGINE_SUBMIT_FAILED`. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: ENGINE_SUBMIT_FAILED message: The engine service rejected or failed the request. securitySchemes: bearerAuth: type: http scheme: bearer description: >- An API key from the web app (**Settings → Developer**), sent as `Authorization: Bearer rvl_live_…`. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.