SI Check for business

A second opinion, inside your product.

The check behind sicheck.com, as an API. Send the message, link or phone number your customer is unsure about. Get back a clear verdict and the evidence behind it, in seconds, ready to show them.

Where it fits

Anywhere people ask you “is this real?” before they click, reply or pay.

  • Marketplaces and classifieds. Check the message or payment link a buyer was sent before they pay a “seller” off the platform.
  • Job boards and recruiters. Flag fake recruiters and task-scam offers before a candidate replies, and show them why.
  • Banks, credit unions and fintechs. Give your support team, and your app, a fast answer to “Is this message really from you?”
  • Help desks, IT teams and MSPs. Let staff check a suspicious email or chat message in one step, with a report the ticket can link to.
  • Telcos, email providers and communities. Put a “check this” button next to messages your users report, and moderate with the evidence in hand.

What the plan includes

  • 1,000 checks a day. Messages, links and phone numbers, through the API, the site and your team’s “Ask me first” links together.
  • The verdict, with its evidence, as JSON. One of four verdicts, a plain summary, every measured signal with its source, the exact words SI flagged (each verified to exist in the text), what to do now, and what couldn’t be checked.
  • One request, one answer. Add ?wait=1 and the finished report comes back in the same response. Or follow progress live over server-sent events.
  • A report page you can hand on. Every check has a private report page. Link your customer to it, or show the verdict in your own design.
  • Everything in Plus, for the account holder. Screenshots and voice notes on the site, the deeper SI reading, detailed analysis and history.
  • Keys you control. Up to five API keys, each named and revocable on your account page. Only a hash of each key is stored.

One request

Full reference: the API documentation.

curl -X POST 'https://sicheck.com/api/v1/checks?wait=1' \
  -H 'authorization: Bearer sic_live_…' \
  -H 'content-type: application/json' \
  -d '{"kind":"text","channel":"sms","input":"Your parcel is on hold. Pay the £1.99 fee at royalmail.rebook-uk.com"}'
{
  "id": "k3q9…", "number": "SC-2026-K3Q9XM", "status": "done",
  "url": "https://sicheck.com/r/k3q9…",
  "report": {
    "verdict": "stop",
    "headline": "A fake delivery fee on an address that isn’t Royal Mail’s",
    "signals": [{ "id": "url.lookalike.in-domain", "label": "Contains the Royal Mail name",
                  "value": "rebook-uk.com", "severity": 2, "measured": true, "source": "…" }, …],
    "observations": [{ "claim": "Asks for a small fee to release a parcel", "quote": "Pay the £1.99 fee", "severity": 3 }],
    "nextSteps": ["Don’t pay or click the link", …],
    "limits": []
  }
}

The same rules as for everyone

Business customers are held to the Charter like everyone else. We don’t sell placement, don’t tune verdicts for customers, and don’t show ads. The money from this plan keeps everyday checking free for the people your customers are, which is the point of it.

Questions about Business

What counts as a check?

One message, link or phone number sent to be checked. Reading a result, following its progress, deleting it and the built-in examples don’t count, and a check that fails on our side is given back.

What if we need more than the daily limit?

Past 1,000 checks in a UTC day the API answers 429 until midnight UTC, so nothing is ever billed by surprise. If you regularly need more, write to hello@sicheck.com and we’ll talk about a plan that fits.

Can a business pay for a different verdict?

No. Your plan buys volume and an integration, never a different answer. A message that mentions your brand gets the same check and the same verdict as anyone else’s, and that is what makes the verdict worth showing to your customers.

What happens to what we send?

The same as on the site. Card, bank, ID and phone numbers and email addresses are masked before SI reads anything. Only the masked report is kept, for 30 days, and you can delete any report sooner through the API. We never sell it or use it for advertising.

Can we show the verdict in our own product?

Yes. Keep the four verdict names as they are (STOP, VERIFY FIRST, NO RED FLAGS, CAN’T TELL), never present NO RED FLAGS as “safe”, and say the check is by SI Check. Linking to the report is the simplest way to do all three.

Is there an SLA?

Not on this plan yet, and we would rather say so. The service runs on Cloudflare’s network. If you need contractual uptime or a data processing agreement, write to hello@sicheck.com.

Can we try it first?

The API returns exactly what a report on sicheck.com shows, so the free checks on the site are a fair trial of the answers. The plan can be cancelled any time, and you keep it until the end of the month you’ve paid for.