@kynth/api

@kynth/api

Official TypeScript SDK for ParseRail — the AI back-end for your product. Parse documents, extract fields, redact PII, analyze contracts, fight chargebacks, and enrich companies through one typed client.

npm i @kynth/api

Quickstart

import { KynthCore } from "@kynth/api";

const kynth = new KynthCore({ apiKey: process.env.KYNTH_API_KEY! });

const doc = await kynth.parse({ fileUrl: "https://…/invoice.pdf" });
console.log(doc.totalAmount);              // 4820.5
console.log(doc.usage.balanceRemaining);   // 490

Get a key (and 500 free credits) at api.kynth.studio. Zero runtime dependencies — works on Node 18+, browsers, and edge/worker runtimes with a global fetch.

Methods

Every method returns the endpoint result plus a usage: { credits, balanceRemaining } envelope. A non-2xx response throws a typed KynthError (and never burns credits).

await kynth.parse({ fileUrl });                              // documents → JSON
await kynth.extract({ text, fields: ["order", "total"] });   // pull named fields
await kynth.classify({ text, labels: ["billing", "tech"] }); // label text
await kynth.summarize({ text, length: "standard" });         // summary + actions
await kynth.redact({ text });                                // strip PII/PHI
await kynth.sentiment({ text, aspects: ["product"] });       // sentiment + aspects
await kynth.contract({ fileUrl });                           // contract → terms + risks
await kynth.chargeback({ reason, transaction, evidence });   // representment packet
await kynth.enrich({ email: "[e-mail]" });             // company profile
await kynth.account();                                       // balance

Async & webhooks

A hundred-page contract doesn't fit in a request/response cycle. The document endpoints — parse, invoice, receipt, statement, resume, tables, split, compare, contract — take async: true and hand you a job instead of a result.

const job = await kynth.parse({ fileUrl, async: true });   // → { jobId, status: "queued" }
const done = await kynth.waitForJob<ParseResult>(job.jobId);

if (done.status === "succeeded") console.log(done.result!.totalAmount);
else console.error(done.error);                            // failed jobs are never charged

async: true narrows the return type to a JobHandle, so the compiler tells you which one you got. Poll a single time with getJob(jobId) if you'd rather drive the loop yourself.

Every job reaches a terminal state. If the instance running yours dies mid-flight, it is marked failed with an explanation rather than left running forever — and you aren't billed for it. Nothing is silently retried; resubmit and you stay in control of the spend.

Webhooks

Pass a callbackUrl (public https) and the finished job is POSTed to it, signed with your account's webhook secret from the API keys page:

await kynth.parse({ fileUrl, async: true, callbackUrl: "https://you.example/hooks/kynth" });

import { createHmac, timingSafeEqual } from "node:crypto";

// X-Kynth-Signature: sha256=<hex HMAC-SHA256 of the RAW body>
function verify(rawBody: string, header: string, secret: string) {
  const expected = createHmac("sha256", secret).update(rawBody).digest("hex");
  const got = header.replace(/^sha256=/, "");
  return got.length === expected.length &&
    timingSafeEqual(Buffer.from(got), Buffer.from(expected));
}

Delivery is best-effort and never retried — polling is the source of truth.

Error handling

import { KynthCore, KynthError } from "@kynth/api";

try {
  await kynth.parse({ fileUrl });
} catch (err) {
  if (err instanceof KynthError) {
    // err.code: "insufficient_credits" | "rate_limited" | "unauthorized" | …
    // err.status: HTTP status
    console.error(err.code, err.message);
  }
}

Options

new KynthCore({
  apiKey: "ksk_live_…",
  baseUrl: "https://api.kynth.studio", // override the origin
  timeoutMs: 60_000,                    // per-request timeout
  fetch: customFetch,                   // inject a fetch implementation
});

Pricing

Pay-per-call credits, no subscription. Each endpoint burns at its own rate (1 credit = $0.01), and you're only charged on a successful call. See api.kynth.studio/docs.

MIT © Kynth Studios