persona sdk patterns | sed 's/\b(.)/\u\1/g'

Overview

Singleton API client, typed verification results, pagination through inquiries, error classification.

Prerequisites

• Completed

  persona-install-auth

  setup
• Valid Persona API key (sandbox or production)

Instructions

Step 1: Typed API Client Wrapper

import axios, { AxiosInstance, AxiosError } from 'axios';

interface PersonaConfig {
  apiKey: string;
  version?: string;
  baseURL?: string;
}

class PersonaClient {
  private http: AxiosInstance;

  constructor(config: PersonaConfig) {
    this.http = axios.create({
      baseURL: config.baseURL || 'https://withpersona.com/api/v1',
      headers: {
        'Authorization': `Bearer ${config.apiKey}`,
        'Persona-Version': config.version || '2023-01-05',
        'Content-Type': 'application/json',
      },
    });
  }

  async createInquiry(templateId: string, referenceId: string, fields?: Record<string, any>) {
    const { data } = await this.http.post('/inquiries', {
      data: { attributes: { 'inquiry-template-id': templateId, 'reference-id': referenceId, fields } },
    });
    return data.data;
  }

  async getInquiry(inquiryId: string) {
    const { data } = await this.http.get(`/inquiries/${inquiryId}`);
    return data.data;
  }

  async listInquiries(params: { referenceId?: string; status?: string; pageSize?: number } = {}) {
    const { data } = await this.http.get('/inquiries', {
      params: {
        'filter[reference-id]': params.referenceId,
        'filter[status]': params.status,
        'page[size]': params.pageSize || 25,
      },
    });
    return data.data;
  }

  async getVerification(verificationId: string) {
    const { data } = await this.http.get(`/verifications/${verificationId}`);
    return data.data;
  }
}

// Singleton
let _client: PersonaClient | null = null;
export function getPersonaClient(): PersonaClient {
  if (!_client) {
    _client = new PersonaClient({ apiKey: process.env.PERSONA_API_KEY! });
  }
  return _client;
}

Step 2: Error Classification

function classifyPersonaError(error: AxiosError): { retryable: boolean; message: string } {
  const status = error.response?.status;
  if (status === 429) return { retryable: true, message: 'Rate limited' };
  if (status && status >= 500) return { retryable: true, message: 'Server error' };
  if (status === 401) return { retryable: false, message: 'Invalid API key' };
  if (status === 422) return { retryable: false, message: 'Invalid request' };
  return { retryable: false, message: error.message };
}

Output

• Typed Persona API client with inquiry and verification methods
• Singleton pattern for reuse
• Error classification for retry decisions
• Paginated inquiry listing

Error Handling

Pattern	Use Case	Benefit
Singleton	All API calls	One client, consistent headers
Error classifier	Retry decisions	Only retry 429/5xx
Typed responses	Data access	Autocomplete, type safety

Resources

• Persona API Reference
• API Introduction

Next Steps

Apply in

persona-core-workflow-a

for real KYC flows.