API documentation

With the Do4U API you use the same tools as on the website from your own software: summarise, compare, support replies, alt texts, rewrite and translate. Every request is processed on our own servers in Poland, EU.

Base URL: https://do4u.eu/api/v1

OpenAPI 3.1 description (JSON) – Machine-readable description of this API for code generators and tools such as Postman or Insomnia. No key needed.

Authentication

Create a key under API keys in your account. Send it with every request in the header Authorization: Bearer <key> (or X-API-Key: <key>). Keep the key secret and never put it into a web page. You can revoke a key at any time.

How it works

Jobs run asynchronously. You create a job and get its id at once (HTTP 202). Then you fetch the job until its status is done or failed. Ask every 2 to 5 seconds; most jobs take a few seconds.

Endpoints

Example

Create a job, then fetch the result:

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"tool": "summarize", "text": "...", "options": {"length": "short"}, "language": "en"}'

HTTP/1.1 202 Accepted
{"id": "8f1c0b6a...", "tool": "summarize", "status": "queued", "model": "do4u-standard",
 "credits_estimate": 1, "links": {"self": "https://do4u.eu/api/v1/jobs/8f1c0b6a..."}}

curl https://do4u.eu/api/v1/jobs/8f1c0b6a... -H "Authorization: Bearer d4u_YOUR_KEY"

{"id": "8f1c0b6a...", "tool": "summarize", "status": "done", "model": "do4u-standard", "credits_estimate": 1,
 "result": {"summary": "...", "key_points": ["...", "..."]}, "credits": 1,
 "notice": "AI-generated, please check before use."}

curl -X POST https://do4u.eu/api/v1/jobs -H "Authorization: Bearer d4u_YOUR_KEY" \
  -F tool=alt_text -F language=de -F "text=Product page: hiking boots" -F image=@photo.jpg

Request fields for POST /jobs

Repeat requests safely (Idempotency-Key)

Send the header Idempotency-Key with POST /jobs, for example a random UUID for each job (1 to 255 printable ASCII characters). If the connection breaks and you send the same request again with the same Idempotency-Key and the same API key within 24 hours, you get the same answer again: the same job, no second job and no second charge. The answer then has the header Idempotent-Replayed: true. Use a new key for every new job. If you send the same key with a different request, you get 422 idempotency_conflict. Errors are not stored: after an error you can send the request again with the same key.

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_YOUR_KEY" \
  -H "Idempotency-Key: 5f0c2a8e-7d1b-4c3a-9e2f-1b6d8a4c0e77" \
  -H "Content-Type: application/json" \
  -d '{"tool": "summarize", "text": "..."}'

Tools and options

Job status

queued and running: still working (position and wait_seconds help you to wait). done: result contains the fields of the tool. failed: nothing was charged (credits is 0); error.code names the reason: address_blocked (Do4U does not open this address, for example a private or internal one; send the text or HTML instead), input_too_large (shorten the input), image_unavailable or job_failed. expired: the result is no longer stored.

Webhooks

Add "callback_url" to POST /api/v1/jobs, and Do4U sends a signed POST (event job.finished with status, credits and the result link - not the result itself) as soon as the job is done. Only public addresses on port 80 or 443; we retry up to 6 times with growing pauses.

Example: create a job with callback_url – and the request Do4U sends to that address when the job is finished:

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"tool": "summarize", "text": "...", "callback_url": "https://example.com/do4u-hook"}'

POST /do4u-hook
Content-Type: application/json
X-Do4U-Event: job.finished
X-Do4U-Signature: t=1793180000,v1=6b1f...

{"event":"job.finished","id":"8f1c0b6a...","tool":"summarize","status":"done","credits":1,
 "created":"2026-10-28T10:00:00+01:00","finished":"2026-10-28T10:00:04+01:00","result_url":"https://do4u.eu/api/v1/jobs/8f1c0b6a..."}

Check the header X-Do4U-Signature: t=<time>,v1=<hex>, where v1 = HMAC-SHA256(secret, "<time>.<raw body>"). Reject old times (e.g. older than 5 minutes). Your secret starts with whsec_ and is shown on the page API keys.

// Node.js: rawBody = the request body exactly as received (string)
const crypto = require('crypto');
function do4uSignatureOk(rawBody, header, secret) {
  const t = (header.match(/t=(\d+)/) || [])[1];
  const v1 = (header.match(/v1=([0-9a-f]{64})/) || [])[1];
  if (!t || !v1 || Math.abs(Date.now() / 1000 - Number(t)) > 300) return false;
  const expected = crypto.createHmac('sha256', secret).update(t + '.' + rawBody).digest('hex');
  return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(v1));
}

// PHP
function do4u_signature_ok(string $raw, string $header, string $secret): bool {
    if (!preg_match('/t=(\d+),v1=([0-9a-f]{64})/', $header, $m) || abs(time() - (int)$m[1]) > 300) return false;
    return hash_equals(hash_hmac('sha256', $m[1] . '.' . $raw, $secret), $m[2]);
}
$ok = do4u_signature_ok(file_get_contents('php://input'), $_SERVER['HTTP_X_DO4U_SIGNATURE'] ?? '', 'whsec_YOUR_SECRET');

credits.low

When the credit balance of an account drops below the threshold, Do4U sends one signed POST to the webhook address of the account. The event contains no personal data, only the balance, the threshold and the time (UTC). The next one follows only after credits were added again (purchase, monthly free credits or voucher). Signature and secret are the same as for job.finished.

POST /do4u-hook
Content-Type: application/json
X-Do4U-Event: credits.low
X-Do4U-Signature: t=1793180000,v1=6b1f...

{"event":"credits.low","balance":18,"threshold":20,"ts":"2026-10-29T10:00:04Z"}

You set the address and the threshold here: API keys

n8n

Ready-made workflow: a webhook receives the call from Do4U, checks the signature, fetches the result and hands it to your next step.

Download the n8n template (JSON)

Template, not yet tested in a real n8n or Make instance – please test the signature check before you use it.

In n8n: Workflows → Import from file. Then enter your secret in the node "Check signature" and your API key in "Do4U: get result", activate the workflow and use the production URL of the webhook as callback_url. Self-hosted n8n needs the environment variable NODE_FUNCTION_ALLOW_BUILTIN=crypto for the signature check.

Make

1. Add the module Webhooks → Custom webhook as the trigger and switch on "JSON pass-through" and "Get request headers" in its advanced settings.
2. Use the address of this webhook as callback_url.
3. Check the signature: compare v1 from the header X-Do4U-Signature with sha256(t + "." + raw body; hex; your secret).
4. Add HTTP → Make a request: GET on result_url with the header Authorization: Bearer <your API key>.
5. Use the field result in your next modules.

Template, not yet tested in a real n8n or Make instance – please test the signature check before you use it.

Recipes: chain tools

A recipe runs 2 to 4 tools one after the other as one job. Send "recipe" instead of "tool": either the name of a ready-made recipe or a list of steps. The text goes into the first step; the result of each step is the text for the next step. GET /api/v1/recipes lists the ready-made recipes, the tools you can use and the field each tool hands on.

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"recipe": [{"tool": "summarize", "options": {"length": "short"}},
               {"tool": "translate", "options": {"target": "pl"}}], "text": "..."}'

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"recipe": "summary_translate_meta", "options": {"target": "pl"}, "text": "..."}'

You get one estimate for all steps (credits_estimate). That amount is reserved at the start. After each step the real use is booked and the rest stays reserved until the end, then it is released. A failed step costs nothing, the remaining steps are skipped, and steps that were already finished are charged.

HTTP/1.1 202 Accepted
{"id": "3c9e0d1a...", "tool": "recipe", "recipe": null, "status": "queued", "model": "do4u-standard", "credits_estimate": 4,
 "steps": [{"n": 1, "tool": "summarize", "credits_estimate": 2}, {"n": 2, "tool": "translate", "credits_estimate": 2}],
 "links": {"self": "https://do4u.eu/api/v1/jobs/3c9e0d1a..."}}

GET /api/v1/jobs/{id} shows every step with its status (pending, queued, running, done, failed, skipped), its credits, a notice input_shortened if the text had to be shortened for the next tool, and the result of each step once the recipe has ended. With no_store the results are shown once. callback_url fires once, at the end of the recipe.

GET https://do4u.eu/api/v1/jobs/3c9e0d1a...

{"id": "3c9e0d1a...", "tool": "recipe", "status": "done", "credits_estimate": 4, "credits": 3, "steps_total": 2,
 "steps": [{"n": 1, "tool": "summarize", "status": "done", "credits": 1, "result": {"summary": "...", "key_points": ["..."]}},
           {"n": 2, "tool": "translate", "status": "done", "credits": 2, "notices": ["input_shortened"], "result": {"translation": "...", "notes": []}}],
 "result": {"translation": "...", "notes": []}}

GET https://do4u.eu/api/v1/recipes

Errors

Errors always have the same form: {"error": {"code": "...", "message": "..."}}. With 429 and 503 the header Retry-After says how many seconds to wait.

Limits

• 60 requests per minute per key and 120 per account.
• Open jobs at the same time per account: Free 3, Starter 3, Standard 5, Pro 10, for the website and the API together.
• Input: Free 8,000 characters, paid packages 30,000. Lower limits per tool: compare 20,000, alt_text 1,000, translate 12,000 (compare: both texts together).
• API keys: Free 1, Starter 1, Standard 5, Pro 10.

Credits

A new job shows an estimate (credits_estimate); charged is the actual use (credits). Failed jobs cost nothing. Free credits are used first.

Data

Inputs and results are stored for 7 days (Free) or 30 days (paid packages), then deleted. Images are deleted right after processing. Results are AI-generated: please check them before you use them.

Answer emails without changing your inbox

Do4U does not run an inbox and never stores access data for your mailbox. Two ways to get reply drafts anyway:

S1 – Template for n8n or Make

1. Trigger: a new email in your mailbox (IMAP trigger in n8n or Make – the access data stays there)
2. POST /api/v1/jobs with tool support_reply, the email text and no_store: true
3. Wait a few seconds and fetch GET /api/v1/jobs/{id} until the status is done
4. Create a draft in your mailbox with the text from result.reply (Gmail or Outlook module)

Download the n8n template (JSON)

In Make, build the same scenario from the modules Email (watch emails), HTTP (make a request), Sleep and Gmail or Outlook (create a draft).

Dev extensions and shop plugins

Extract the ZIP and read the included guide. Load the browser extension locally; check shop plugins in a test shop first. Your own Dev API key is required. Shopware currently provides a CLI.

• Do4U for WordPress (ZIP)
• Chrome / Firefox · Dev (ZIP)
• WooCommerce · Dev (ZIP)
• Shopware · CLI · Dev (ZIP)