Quickstart Tutorial

Protect your first image and get back its SignatureID. The tutorial takes about 10 minutes.

Steps

1. Get an access token.
2. Submit an image.
3. Poll the job until it completes.
4. Download the protected image.

Before you start

• A Client ID and Client Secret from SASHA (Prerequisites)
• A JPEG or PNG image, as a public URL or a local file
• A terminal

tip

This tutorial polls for job status. In production, set up callbacks instead: SASHA posts the finished job to your endpoint, so your service makes no status requests.

gRPC prerequisites

For gRPC you also need a gRPC client such as nice-grpc (external link), and client code generated from the SASHA .proto files.

Step 1: Get an access token

Exchange your client credentials for an access token.

REST

Replace YOUR_CLIENT_ID and YOUR_CLIENT_SECRET with your own credentials:

curl https://partner.api.sasha.eu/oauth/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -u "YOUR_CLIENT_ID:YOUR_CLIENT_SECRET" \
  -d "grant_type=client_credentials"

Response:

{
  "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "token_type": "Bearer",
  "expires_in": 3600
}

info

Keep the access_token value for the next steps. The token expires after expires_in seconds.

gRPC

import { createChannel, createClient } from "nice-grpc";
import { PartnerAPIClient } from "./generated/partner_api_grpc_pb.js";

const channel = createChannel("partner.api.sasha.eu:443");
const client = createClient(PartnerAPIClient, channel);

const authResponse = await client.authenticateWithClientCredential({
  clientId: "YOUR_CLIENT_ID",
  clientSecret: "YOUR_CLIENT_SECRET",
});

const accessToken = authResponse.accessToken;
console.log("Access token:", accessToken);

info

Keep the accessToken value for the next steps.

Step 2: Submit the image

Submit the image URL to the Partner API. SASHA fetches the image and returns a job.

REST

curl https://partner.api.sasha.eu/signature/embed \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "media_url": "https://developer.sasha.eu/img/sasha-logo-wall.jpeg",
    "media_mime_type": "image/jpeg"
  }'

Response:

{
  "job": {
    "job_id": "44cab986-0385-470a-8e5c-c657b0543d19",
    "type": "embed-signature",
    "status": "pending",
    "created_at": "2025-10-07T12:00:00Z",
    "updated_at": "2025-10-07T12:00:00Z"
  }
}

info

Keep the job_id value. Step 3 uses it to read the job status.

Alternative: upload the file directly

To send a local file, use multipart/form-data (REST) or the EmbedSignatureFromData streaming method (gRPC). See Embed Signature.

gRPC

import { createChannel, createClient, Metadata } from "nice-grpc";
import { PartnerServiceClient } from "./generated/partner_grpc_pb.js";

const partnerChannel = createChannel("partner.api.sasha.eu:443");
const partnerClient = createClient(PartnerServiceClient, partnerChannel);

// Create metadata with authorization token
const metadata = new Metadata();
metadata.set("authorization", `Bearer ${accessToken}`);

// Submit image for protection
const embedResponse = await partnerClient.embedSignatureFromURL(
  {
    mediaUrl: "https://developer.sasha.eu/img/sasha-logo-wall.jpeg",
    mediaMimeType: "image/jpeg",
  },
  { metadata }
);

const jobId = embedResponse.job.jobId;
console.log("Job ID:", jobId);
console.log("Job status:", embedResponse.job.status);

Alternative: stream the file data

To send a local file, use the EmbedSignatureFromData streaming method. See the gRPC API Reference.

Step 3: Poll the job

Read the job every 2 seconds until status is completed. Most jobs complete within 1 second.

REST

curl https://partner.api.sasha.eu/jobs/44cab986-0385-470a-8e5c-c657b0543d19 \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN"

Response (while processing):

{
  "job_id": "44cab986-0385-470a-8e5c-c657b0543d19",
  "type": "embed-signature",
  "status": "in_progress",
  "created_at": "2025-10-07T12:00:00Z",
  "updated_at": "2025-10-07T12:00:01Z"
}

Response (when complete):

{
  "job_id": "44cab986-0385-470a-8e5c-c657b0543d19",
  "type": "embed-signature",
  "status": "completed",
  "output_url": "https://storage.sasha.eu/protected/abc123.jpg",
  "output_url_expires_at": "2025-10-07T13:00:00Z",
  "signature_id": "12345678901234567890",
  "creator_id": 123,
  "created_at": "2025-10-07T12:00:00Z",
  "updated_at": "2025-10-07T12:00:05Z"
}

gRPC

const waitForCompletion = async (jobId) => {
  while (true) {
    const jobResponse = await partnerClient.getJob(
      { jobId },
      { metadata }
    );

    console.log("Job status:", jobResponse.status);

    if (jobResponse.status === "completed") {
      return jobResponse;
    }

    if (jobResponse.status === "failed") {
      throw new Error(`Job failed: ${jobResponse.error.message}`);
    }

    // Wait 2 seconds before reading the job again
    await new Promise((resolve) => setTimeout(resolve, 2000));
  }
};

const completedJob = await waitForCompletion(jobId);
console.log("Protected image URL:", completedJob.outputUrl);
console.log("Signature ID:", completedJob.signatureId);

Step 4: Download the protected image

Download the image from output_url.

REST

curl -o protected-image.jpg "https://storage.sasha.eu/protected/abc123.jpg"

The URL expires

output_url stops working at the time in output_url_expires_at. Download the image before then.

gRPC

import { writeFileSync } from "fs";

const imageResponse = await fetch(completedJob.outputUrl);
const imageBuffer = await imageResponse.arrayBuffer();
writeFileSync("protected-image.jpg", Buffer.from(imageBuffer));

console.log("Protected image saved");

The URL expires

The output URL stops working at the time in outputUrlExpiresAt. Download the image before then.

Result

You now have:

• job_id — the identifier of the embed job
• signature_id — the public handle for this Signature
• creator_id — the CreatorID of the partner that protected the image
• A protected image that looks identical to the original and carries the Signature

Look the Signature up

Confirm the Signature is in the image by looking it up.

REST

curl https://partner.api.sasha.eu/signature/lookup \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "media_url": "[USE_OUTPUT_URL_FROM_STEP_3]",
    "media_mime_type": "image/jpeg"
  }'

Replace [USE_OUTPUT_URL_FROM_STEP_3] with the output_url from Step 3.

gRPC

const lookupResponse = await partnerClient.lookupSignatureFromURL(
  {
    mediaUrl: completedJob.outputUrl,
    mediaMimeType: "image/jpeg",
  },
  { metadata }
);

// Wait for the lookup job to complete, the same way as the embed job
const lookupResult = await waitForCompletion(lookupResponse.job.jobId);
console.log("Found signature ID:", lookupResult.signatureId);

The signature_id the lookup returns matches the one from your embed job.

Common issues

401 Unauthorized	The token expired, or the credentials are wrong. Request a new token.
400 Bad Request, media_url is required	Send media_url and media_mime_type in a JSON body.
Job status is failed, error unsupported_format	Convert the image to JPEG or PNG.
404 Not Found on output_url	The URL expired. Read output_url_expires_at, then run the embed job again.

Next steps

• Authentication — token lifetime and renewal
• Signature — what a Signature is and how it survives editing
• Callbacks — receive the finished job instead of polling for it
• Rate limiting — what a 429 means and how to recover
• REST API Reference — every endpoint, field, and error code
• gRPC API Reference — every RPC and message

Before you go to production

1. Replace polling with callbacks.
2. Cache the access token. Renew it 60 seconds before expires_in.
3. Retry a failed job only on failed_to_fetch_from_url and internal.