Constructing dynamic Genesys Cloud Custom Action queries using a TypeScript GraphQL builder that maps user inputs to schema fields, handles variable interpolation, and validates response types against Zod definitions

What You Will Build

• A TypeScript utility that dynamically constructs Genesys Cloud GraphQL queries for Custom Actions by mapping runtime inputs to schema fields, injecting type-safe variables, and validating responses against Zod schemas.
• Uses the official Genesys Cloud GraphQL endpoint (/api/v2/graphql) with cursor-based pagination and exponential backoff retry logic.
• Covers TypeScript (Node.js 18+) with native fetch, zod, and standard OAuth2 client credentials authentication.

Prerequisites

• OAuth2 machine-to-machine client with customactions:read scope
• Genesys Cloud API v2 GraphQL endpoint
• Node.js 18 or later (native fetch support)
• Dependencies: zod@^3.22, dotenv@^16.3
• Environment variables: GENESYS_CLIENT_ID, GENESYS_CLIENT_SECRET, GENESYS_ENV (defaults to api.mypurecloud.com)

Authentication Setup

The Genesys Cloud GraphQL endpoint requires a valid bearer token. The client credentials flow exchanges your application credentials for a short-lived access token. Token caching prevents unnecessary network calls and respects the expires_in window.

// auth.ts
import { z } from 'zod';

const TokenResponseSchema = z.object({
  access_token: z.string(),
  token_type: z.literal('Bearer'),
  expires_in: z.number(),
  scope: z.string()
});

interface AuthConfig {
  clientId: string;
  clientSecret: string;
  scopes: string[];
  baseUrl: string;
}

export class GenesysAuth {
  private token: string | null = null;
  private expiresAt: number = 0;
  private config: AuthConfig;

  constructor(config: AuthConfig) {
    this.config = config;
  }

  async getToken(): Promise<string> {
    if (this.token && Date.now() < this.expiresAt) {
      return this.token;
    }

    const params = new URLSearchParams({
      grant_type: 'client_credentials',
      client_id: this.config.clientId,
      client_secret: this.config.clientSecret,
      scope: this.config.scopes.join(' ')
    });

    const response = await fetch(`${this.config.baseUrl}/oauth/token`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
      body: params
    });

    if (!response.ok) {
      const errorText = await response.text();
      throw new Error(`OAuth token request failed with status ${response.status}: ${errorText}`);
    }

    const rawData = await response.json();
    const parsed = TokenResponseSchema.parse(rawData);

    this.token = parsed.access_token;
    this.expiresAt = Date.now() + (parsed.expires_in * 1000);

    return this.token;
  }
}

Required OAuth scope: customactions:read
HTTP cycle: POST /oauth/token with application/x-www-form-urlencoded body. Returns JSON containing access_token and expires_in.

Implementation

Step 1: Schema Field Mapping & Query Construction

Dynamic GraphQL builders must prevent injection and enforce schema compliance. The builder accepts a field mapping configuration that restricts selectable fields and maps user input keys to GraphQL variable names. This design prevents runtime schema drift and ensures only validated fields reach the API.

// builder.ts
import { z } from 'zod';

export interface FieldMapping {
  inputKey: string;
  graphqlField: string;
  variableType: 'String' | 'Int' | 'Boolean' | 'ID';
  isFilter?: boolean;
}

export interface QueryConfig {
  rootField: string;
  allowedSelections: string[];
  fieldMappings: FieldMapping[];
  pageSize?: number;
}

export class GenesysGraphQLBuilder {
  private config: QueryConfig;

  constructor(config: QueryConfig) {
    this.config = config;
  }

  buildQuery(selections: string[], userInput: Record<string, any>, cursor?: string) {
    const validSelections = selections.filter(s => this.config.allowedSelections.includes(s));
    const selectionBlock = validSelections.map(field => `        ${field}`).join('\n');

    const variables: Record<string, any> = {};
    const filterConditions: string[] = [];

    for (const mapping of this.config.fieldMappings) {
      if (Object.prototype.hasOwnProperty.call(userInput, mapping.inputKey)) {
        variables[mapping.graphqlField] = userInput[mapping.inputKey];
        filterConditions.push(`${mapping.graphqlField}: $${mapping.graphqlField}`);
      }
    }

    variables.first = this.config.pageSize ?? 50;
    if (cursor) {
      variables.after = cursor;
    }

    const varDefinitions = Object.entries(variables)
      .map(([key, value]) => {
        const type = this.resolveGraphQLType(value);
        return `    $${key}: ${type}!`;
      })
      .join('\n');

    const filterArgs = filterConditions.length > 0 
      ? `filter: { ${filterConditions.join(', ')} }` 
      : '';

    const paginationArgs = [
      filterArgs,
      'first: $first',
      'after: $after'
    ].filter(Boolean).join(',\n      ');

    const query = `
      query FetchCustomActions(
${varDefinitions}
      ) {
        ${this.config.rootField}(${paginationArgs}) {
          pageInfo {
            hasNextPage
            endCursor
          }
          edges {
            node {
${selectionBlock}
            }
          }
        }
      }
    `;

    return { query, variables };
  }

  private resolveGraphQLType(value: unknown): string {
    if (typeof value === 'boolean') return 'Boolean';
    if (typeof value === 'number') return 'Int';
    if (typeof value === 'string') return 'String';
    return 'String';
  }
}

Design rationale: The builder separates field selection from filter variable generation. GraphQL does not allow dynamic field names in the query string without risking syntax errors. By filtering against allowedSelections, the builder guarantees valid AST structure. Variable definitions are generated at runtime based on actual input types, preventing type mismatch errors on the server side.

Step 2: Variable Interpolation & Execution with Retry Logic

GraphQL endpoints accept queries and variables in the request body. The executor handles token injection, payload serialization, and automatic retry on rate limits. Genesys Cloud returns 429 with a Retry-After header during throttling. The executor parses this header and applies exponential backoff with jitter to prevent thundering herd scenarios.

// executor.ts
import { z } from 'zod';

const GraphQLResponseSchema = z.object({
  data: z.any().nullable(),
  errors: z.array(z.object({
    message: z.string(),
    path: z.array(z.string()).optional(),
    extensions: z.any().optional()
  })).optional()
});

interface ExecutionOptions {
  baseUrl: string;
  getToken: () => Promise<string>;
  maxRetries: number;
  baseDelayMs: number;
}

export class GenesysGraphQLExecutor {
  private options: ExecutionOptions;

  constructor(options: ExecutionOptions) {
    this.options = options;
  }

  async execute<T>(query: string, variables: Record<string, any>, zodSchema: z.ZodType<T>): Promise<T> {
    let attempts = 0;
    let delay = this.options.baseDelayMs;

    while (attempts < this.options.maxRetries) {
      const token = await this.options.getToken();

      const response = await fetch(`${this.options.baseUrl}/api/v2/graphql`, {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${token}`,
          'Content-Type': 'application/json',
          'Accept': 'application/json'
        },
        body: JSON.stringify({ query, variables })
      });

      if (response.status === 429) {
        const retryAfter = response.headers.get('Retry-After');
        const waitTime = retryAfter 
          ? parseInt(retryAfter, 10) * 1000 
          : delay + (Math.random() * 500);
        
        console.warn(`Rate limited. Retrying in ${waitTime}ms (attempt ${attempts + 1}/${this.options.maxRetries})`);
        await new Promise(resolve => setTimeout(resolve, waitTime));
        delay *= 2;
        attempts++;
        continue;
      }

      if (!response.ok) {
        const errorBody = await response.text();
        throw new Error(`GraphQL request failed with status ${response.status}: ${errorBody}`);
      }

      const rawData = await response.json();
      const parsed = GraphQLResponseSchema.parse(rawData);

      if (parsed.errors && parsed.errors.length > 0) {
        throw new Error(`GraphQL execution errors: ${JSON.stringify(parsed.errors)}`);
      }

      return zodSchema.parse(parsed.data);
    }

    throw new Error(`Max retry attempts (${this.options.maxRetries}) exceeded for GraphQL request`);
  }
}

Required OAuth scope: customactions:read
HTTP cycle: POST /api/v2/graphql with JSON body { "query": "...", "variables": {...} }. Returns JSON with data and optional errors array.

Step 3: Processing Results & Zod Validation

Response validation prevents runtime crashes when the API schema changes or returns unexpected null values. Zod schemas define the exact shape of the returned edges and page info. The builder returns a typed result object that includes pagination cursors for subsequent requests.

// types.ts
import { z } from 'zod';

export const CustomActionNodeSchema = z.object({
  id: z.string(),
  name: z.string(),
  active: z.boolean(),
  version: z.number().optional(),
  createdDate: z.string().datetime().optional(),
  updatedDate: z.string().datetime().optional()
});

export const CustomActionEdgeSchema = z.object({
  node: CustomActionNodeSchema,
  cursor: z.string()
});

export const PageInfoSchema = z.object({
  hasNextPage: z.boolean(),
  endCursor: z.string().nullable()
});

export const CustomActionListResponseSchema = z.object({
  customActions: z.object({
    pageInfo: PageInfoSchema,
    edges: z.array(CustomActionEdgeSchema)
  })
});

export type CustomActionNode = z.infer<typeof CustomActionNodeSchema>;
export type CustomActionListResponse = z.infer<typeof CustomActionListResponseSchema>;

The Zod definitions enforce strict typing. When the API returns a field with an unexpected type or omits a required field, .parse() throws a descriptive error with the exact path. This prevents silent data corruption in downstream processing.

Complete Working Example

The following script combines authentication, query building, execution, and pagination into a single runnable module. Replace the environment variables with your Genesys Cloud credentials.

// main.ts
import { GenesysAuth } from './auth';
import { GenesysGraphQLBuilder } from './builder';
import { GenesysGraphQLExecutor } from './executor';
import { CustomActionListResponseSchema, CustomActionNode } from './types';

async function run() {
  const ENV = process.env.GENESYS_ENV || 'api.mypurecloud.com';
  const CLIENT_ID = process.env.GENESYS_CLIENT_ID!;
  const CLIENT_SECRET = process.env.GENESYS_CLIENT_SECRET!;

  const auth = new GenesysAuth({
    clientId: CLIENT_ID,
    clientSecret: CLIENT_SECRET,
    scopes: ['customactions:read'],
    baseUrl: `https://${ENV}`
  });

  const builder = new GenesysGraphQLBuilder({
    rootField: 'customActions',
    allowedSelections: ['id', 'name', 'active', 'version', 'createdDate', 'updatedDate'],
    fieldMappings: [
      { inputKey: 'nameFilter', graphqlField: 'nameContains', variableType: 'String', isFilter: true },
      { inputKey: 'isActive', graphqlField: 'active', variableType: 'Boolean', isFilter: true },
      { inputKey: 'minVersion', graphqlField: 'versionGte', variableType: 'Int', isFilter: true }
    ],
    pageSize: 10
  });

  const executor = new GenesysGraphQLExecutor({
    baseUrl: `https://${ENV}`,
    getToken: () => auth.getToken(),
    maxRetries: 3,
    baseDelayMs: 1000
  });

  const userInput = {
    nameFilter: 'Deploy',
    isActive: true
  };

  const requestedFields = ['id', 'name', 'active', 'version'];
  let allNodes: CustomActionNode[] = [];
  let cursor: string | undefined;
  let hasMore = true;

  console.log('Starting paginated Custom Action retrieval...');

  while (hasMore) {
    const { query, variables } = builder.buildQuery(requestedFields, userInput, cursor);
    
    const result: z.infer<typeof CustomActionListResponseSchema> = await executor.execute(
      query,
      variables,
      CustomActionListResponseSchema
    );

    const nodes = result.customActions.edges.map(e => e.node);
    allNodes.push(...nodes);

    console.log(`Fetched ${nodes.length} records. Total so far: ${allNodes.length}`);

    hasMore = result.customActions.pageInfo.hasNextPage;
    cursor = result.customActions.pageInfo.endCursor ?? undefined;
  }

  console.log(`Complete. Retrieved ${allNodes.length} Custom Actions.`);
  console.log('Sample record:', JSON.stringify(allNodes[0], null, 2));
}

run().catch(err => {
  console.error('Execution failed:', err.message);
  process.exit(1);
});

Required OAuth scope: customactions:read
Execution flow: The script initializes authentication, configures the builder with allowed fields and filter mappings, executes paginated requests, validates each response against Zod, and accumulates results until hasNextPage is false.

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The access token has expired or the client credentials are invalid.
• Fix: Verify GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET match a registered OAuth client in the Genesys Cloud admin portal. Ensure the token cache expires correctly. The GenesysAuth class automatically refreshes when Date.now() >= expiresAt.
• Code fix: Add explicit token validation before execution:

const token = await auth.getToken();
if (!token) throw new Error('Failed to retrieve valid OAuth token');

Error: 403 Forbidden

• Cause: The OAuth client lacks the customactions:read scope, or the application is restricted to a specific environment.
• Fix: Navigate to the Genesys Cloud OAuth client configuration and add customactions:read to the allowed scopes. Confirm the environment URL matches the client registration.
• Code fix: Log the exact scope returned during token acquisition:

const parsed = TokenResponseSchema.parse(rawData);
console.log('Granted scopes:', parsed.scope);

Error: 429 Too Many Requests

• Cause: The application exceeded Genesys Cloud rate limits for GraphQL queries.
• Fix: The GenesysGraphQLExecutor implements exponential backoff with jitter. If failures persist, reduce pageSize in the builder configuration or implement request queuing. Parse the Retry-After header for server-suggested wait times.
• Code fix: Increase retry tolerance and log wait times:

if (response.status === 429) {
  const retryAfter = response.headers.get('Retry-After');
  const waitTime = retryAfter ? parseInt(retryAfter, 10) * 1000 : delay;
  await new Promise(resolve => setTimeout(resolve, waitTime));
  delay *= 2;
  attempts++;
  continue;
}

Error: Zod validation error

• Cause: The API response structure differs from the Zod schema, or a field returned null when a non-nullable type was expected.
• Fix: Inspect the raw response body before parsing. Update the Zod schema to match actual API output. Use .optional() or .nullable() for fields that may be absent.
• Code fix: Catch and log validation paths:

try {
  return zodSchema.parse(parsed.data);
} catch (validationError) {
  if (validationError instanceof z.ZodError) {
    console.error('Zod validation failed:', JSON.stringify(validationError.errors, null, 2));
  }
  throw validationError;
}

Error: GraphQL errors array populated

• Cause: Invalid variable types, missing required arguments, or unauthorized field access in the query string.
• Fix: Validate that all variable definitions match the GraphQL schema types. Ensure allowedSelections only contains fields exposed by the customActions type. Check that filter arguments use correct GraphQL operator names.
• Code fix: Surface GraphQL errors before Zod validation:

if (parsed.errors && parsed.errors.length > 0) {
  const messages = parsed.errors.map(e => `[${e.path?.join('.') || 'root'}] ${e.message}`).join('; ');
  throw new Error(`GraphQL execution failed: ${messages}`);
}

Official References

• Genesys Cloud GraphQL API Documentation
• Genesys Cloud OAuth 2.0 Client Credentials Flow
• Zod Schema Validation Reference
• GraphQL Cursor Pagination Specification