Bun

bun add @constaia/sdk

CONSTAIA_API_KEY=ck_test_...
CONSTAIA_WEBHOOK_SECRET=whsec_...

import { Constaia, ConstaiaError } from "@constaia/sdk";

const constaia = new Constaia();
const path = Bun.argv[2] ?? "dni_valid.jpg";

try {
  const analysis = await constaia.analyze(Bun.file(path), {
    filename: path.split("/").pop(),
    expect: "es_dni",
    checks: { notExpired: true },
    language: "en",
  });
  console.log(analysis.verdict?.status, analysis.verdict?.reasons.map((r) => r.message));
  console.log(analysis.fields.document_number?.value);
} catch (error) {
  if (!(error instanceof ConstaiaError)) throw error;
  console.error(error.name, error.code, error.message, error.requestId);
  process.exitCode = 1;
}

bun run scripts/verify.ts dni_valid.jpg

valid [ "The document is Spanish ID card (DNI).", "Valid until 12/03/2031." ]
12345678Z

import {
  AuthenticationError,
  ConstaiaError,
  InsufficientCreditsError,
  InvalidRequestError,
  PermissionError,
  RateLimitError,
  type Analysis,
  type WebhookEvent,
} from "@constaia/sdk";

// What you send back to the browser (and what the widget renders): no extracted fields.
export function publicResult(analysis: Analysis) {
  const { id, object, status, document, verdict, warnings } = analysis;
  return { id, object, status, document, verdict, warnings };
}

const httpError = (status: number, code: string, message: string, retryAfter?: number) =>
  Response.json(
    { error: { code, message } },
    { status, headers: retryAfter ? { "Retry-After": String(retryAfter) } : undefined },
  );

export function errorResponse(error: unknown): Response {
  if (error instanceof InvalidRequestError) {
    // Unreadable file, unsupported format, too many pages…: the user can fix it.
    return httpError(error.status === 413 ? 413 : 422, error.code ?? "invalid_request", error.message);
  }
  if (error instanceof RateLimitError) {
    const wait = Math.ceil(error.retryAfter ?? 1);
    return httpError(429, "rate_limited", "Too many requests. Try again in a few seconds.", wait);
  }
  if (error instanceof InsufficientCreditsError) {
    console.error("[constaia] Out of credits. Top up at https://app.constaia.com", error.requestId);
    return httpError(503, "unavailable", "Document validation is temporarily unavailable.");
  }
  if (error instanceof AuthenticationError || error instanceof PermissionError) {
    console.error("[constaia] Check CONSTAIA_API_KEY", error.code, error.requestId);
    return httpError(500, "misconfigured", "Server configuration error.");
  }
  if (error instanceof ConstaiaError) {
    // APIError (5xx), APIConnectionError, APITimeoutError
    console.error("[constaia]", error.name, error.code, error.requestId);
    return httpError(502, "upstream_error", "The document could not be analysed. Please try again.");
  }
  console.error(error);
  return httpError(500, "internal_error", "Internal error.");
}

// Dedupe by webhook-id. In production, use a table with a unique key.
const processed = new Set<string>();
export const alreadyProcessed = (webhookId: string) => processed.has(webhookId);
export const markProcessed = (webhookId: string) => void processed.add(webhookId);

export async function handleEvent(event: WebhookEvent) {
  switch (event.type) {
    case "analysis.completed":
      // event.data is the full analysis (with fields). Store it by event.data.id.
      console.log("analysis.completed", event.data.id, event.data.verdict?.status);
      break;
    case "analysis.review_required":
      console.log("Needs manual review", event.data.id);
      break;
    case "analysis.failed":
      console.warn("analysis.failed", event.data.id, event.data.error?.code);
      break;
    case "credits.low":
      console.warn("Credits running low: top up at https://app.constaia.com");
      break;
  }
}

import { Constaia, WebhookVerificationError } from "@constaia/sdk";
import { alreadyProcessed, errorResponse, handleEvent, markProcessed, publicResult } from "./constaia.ts";

const constaia = new Constaia();
const webhookSecret = Bun.env.CONSTAIA_WEBHOOK_SECRET!;

const server = Bun.serve({
  port: Number(Bun.env.PORT ?? 3000),
  // By default Bun closes idle connections after 10 s; an analysis can take up to 30 s.
  idleTimeout: 120,
  maxRequestBodySize: 21 * 1024 * 1024,

  routes: {
    // Put your authentication here: only signed-in users should spend credits.
    "/api/verify-dni": {
      POST: async (req) => {
        const form = await req.formData().catch(() => null);
        const file = form?.get("file");
        if (!(file instanceof File) || file.size === 0) {
          return Response.json({ error: { code: "missing_file", message: "No file received." } }, { status: 400 });
        }
        // Even better: the authenticated user's name, not the form's.
        const fullName = String(form?.get("full_name") ?? "").trim();

        try {
          const analysis = await constaia.analyze(file, {
            expect: "es_dni",
            checks: { notExpired: true, ...(fullName ? { holder: { fullName } } : {}) },
            storage: "none",
            language: "en",
          });
          // Store analysis.id and analysis.verdict in your database.
          return Response.json(publicResult(analysis), { status: analysis.status === "completed" ? 200 : 202 });
        } catch (error) {
          return errorResponse(error);
        }
      },
    },

    "/webhooks/constaia": {
      POST: async (req) => {
        const rawBody = await req.text();
        let event;
        try {
          event = await constaia.webhooks.verify(rawBody, req.headers, webhookSecret);
        } catch (error) {
          if (error instanceof WebhookVerificationError) return new Response("Invalid signature", { status: 400 });
          throw error;
        }

        const webhookId = req.headers.get("webhook-id")!;
        if (!alreadyProcessed(webhookId)) {
          await handleEvent(event);
          markProcessed(webhookId);
        }
        return new Response(null, { status: 204 });
      },
    },
  },

  fetch() {
    return new Response("Not found", { status: 404 });
  },
});

console.log(`http://localhost:${server.port}`);

bun run src/server.ts

{
  "id": "an_01J…",
  "object": "analysis",
  "status": "completed",
  "document": { "type": "es_dni", "label": "Spanish ID card (DNI)", "confidence": 0.97, "side": "both", "country": "ESP" },
  "verdict": {
    "expected": ["es_dni"],
    "match": true,
    "status": "valid",
    "reasons": [
      { "code": "type_match", "severity": "info", "message": "The document is Spanish ID card (DNI)." },
      { "code": "not_expired", "severity": "info", "message": "Valid until 12/03/2031." },
      { "code": "holder", "severity": "info", "message": "…" }
    ]
  },
  "warnings": []
}

curl -F "file=@dni_valid.jpg" -F "full_name=María García López" http://localhost:3000/api/verify-dni

import { signWebhook } from "@constaia/sdk";

const body = JSON.stringify({
  type: "analysis.completed",
  created_at: new Date().toISOString(),
  data: { id: "an_test", object: "analysis", status: "completed", verdict: { status: "valid", reasons: [] } },
});
const headers = await signWebhook(body, Bun.env.CONSTAIA_WEBHOOK_SECRET!);

const res = await fetch("http://localhost:3000/webhooks/constaia", {
  method: "POST",
  headers: { ...headers, "content-type": "application/json" },
  body,
});
console.log(res.status); // 204