> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> Authenticate requests to the ABBYY Vantage API: choose an OAuth 2.0 flow (Authorization Code, Client Credentials, or Password) and pass the access token.

export const VantageRegion = ({children}) => {
  const STORAGE_KEY = "abbyy.vantage.region";
  const REGIONS = [{
    code: "eu",
    label: "Europe"
  }, {
    code: "us",
    label: "North America"
  }, {
    code: "au",
    label: "Australia / Asia-Pacific"
  }];
  const [region, setRegion] = useState("eu");
  const [open, setOpen] = useState(false);
  const containerRef = useRef(null);
  const dropdownRef = useRef(null);
  function safeGetSavedRegion() {
    try {
      const saved = typeof window !== "undefined" ? window.localStorage.getItem(STORAGE_KEY) : null;
      const valid = new Set(REGIONS.map(r => r.code));
      return saved && valid.has(saved) ? saved : "eu";
    } catch {
      return "eu";
    }
  }
  function safeSetSavedRegion(code) {
    try {
      if (typeof window !== "undefined") {
        window.localStorage.setItem(STORAGE_KEY, code);
      }
    } catch {}
  }
  function dispatchRegionChanged(code) {
    try {
      if (typeof window !== "undefined") {
        window.dispatchEvent(new CustomEvent("abbyy:region-changed", {
          detail: {
            code
          }
        }));
      }
    } catch {}
  }
  function replaceRegionInString(text, currentRegion) {
    if (typeof text !== "string") return text;
    const hostRegex = /https:\/\/vantage-(eu|us|au)\.abbyy\.com/gi;
    const tokenRegex = /https:\/\/vantage-\[region\]\.abbyy\.com/gi;
    const bareHostRegex = /vantage-(eu|us|au)\.abbyy\.com/gi;
    const bareTokenRegex = /vantage-\[region\]\.abbyy\.com/gi;
    return text.replace(hostRegex, `https://vantage-${currentRegion}.abbyy.com`).replace(tokenRegex, `https://vantage-${currentRegion}.abbyy.com`).replace(bareHostRegex, `vantage-${currentRegion}.abbyy.com`).replace(bareTokenRegex, `vantage-${currentRegion}.abbyy.com`);
  }
  useEffect(() => {
    setRegion(safeGetSavedRegion());
  }, []);
  useEffect(() => {
    const root = containerRef.current;
    if (!root) return;
    const anchors = root.querySelectorAll("a[href]");
    anchors.forEach(a => {
      const href = a.getAttribute("href");
      if (href) {
        const next = replaceRegionInString(href, region);
        if (next !== href) {
          a.setAttribute("href", next);
        }
      }
    });
    const walker = typeof document !== "undefined" ? document.createTreeWalker(root, NodeFilter.SHOW_TEXT, null) : null;
    if (walker) {
      const toUpdate = [];
      let node = walker.nextNode();
      while (node) {
        const updated = replaceRegionInString(node.nodeValue, region);
        if (updated !== node.nodeValue) {
          toUpdate.push([node, updated]);
        }
        node = walker.nextNode();
      }
      toUpdate.forEach(([textNode, value]) => {
        textNode.nodeValue = value;
      });
    }
  }, [region, children]);
  useEffect(() => {
    const root = containerRef.current;
    if (!root) return;
    const anchors = root.querySelectorAll("a[href]");
    anchors.forEach(a => {
      a.style.fontWeight = "600";
      a.style.textDecoration = "underline";
      a.style.textUnderlineOffset = "2px";
    });
  }, [region, children]);
  useEffect(() => {
    const onRegionChanged = evt => {
      const code = evt && evt.detail && evt.detail.code;
      if (!code || code === region) return;
      setRegion(code);
    };
    if (typeof window !== "undefined") {
      window.addEventListener("abbyy:region-changed", onRegionChanged);
    }
    return () => {
      if (typeof window !== "undefined") {
        window.removeEventListener("abbyy:region-changed", onRegionChanged);
      }
    };
  }, [region]);
  useEffect(() => {
    const onClickAway = e => {
      if (!dropdownRef.current) return;
      if (!dropdownRef.current.contains(e.target)) {
        setOpen(false);
      }
    };
    document.addEventListener("click", onClickAway, true);
    return () => document.removeEventListener("click", onClickAway, true);
  }, []);
  const onSelect = code => {
    setRegion(code);
    safeSetSavedRegion(code);
    dispatchRegionChanged(code);
    setOpen(false);
  };
  const current = REGIONS.find(r => r.code === region) || REGIONS[0];
  return <div className="not-prose">
      <div className="mb-4 inline-flex items-center gap-2" ref={dropdownRef}>
        <span className="text-sm text-zinc-950/80 dark:text-white/80">Tenant Region:</span>
        <div className="relative">
          <button type="button" aria-haspopup="listbox" aria-expanded={open ? "true" : "false"} onClick={() => setOpen(v => !v)} className="h-8 px-3 rounded-md bg-zinc-900/5 dark:bg-white/5 border border-zinc-950/20 dark:border-white/20 text-sm inline-flex items-center gap-2">
            <span className="text-zinc-950 dark:text-white">{current.label}</span>
            <svg width="8" height="24" viewBox="0 -9 3 24" className="transition-transform text-gray-400 overflow-visible dark:text-gray-600 ml-auto" style={{
    transform: open ? "rotate(270deg)" : "rotate(90deg)"
  }}>
              <path d="M0 0L3 3L0 6" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round"></path>
            </svg>
          </button>
          {open ? <div role="listbox" className="absolute z-50 left-full top-0 ml-2 w-56 rounded-xl border border-zinc-950/20 dark:border-white/20 bg-white dark:bg-zinc-900 shadow-lg p-2">
              {REGIONS.map(r => {
    const selected = r.code === region;
    return <button key={r.code} type="button" role="option" aria-selected={selected ? "true" : "false"} onClick={() => onSelect(r.code)} className={"w-full flex items-center justify-between px-3 py-2 rounded-lg text-sm hover:bg-zinc-950/5 dark:hover:bg-white/10 text-zinc-950 dark:text-white" + (selected ? " font-medium" : "")}>
                    <span style={selected ? {
      color: "#ff2038"
    } : undefined}>{r.label}</span>
                    <span className={selected ? "ml-3" : "ml-3 invisible"} style={selected ? {
      color: "#ff2038"
    } : undefined}>✓</span>
                  </button>;
  })}
            </div> : null}
        </div>
      </div>
      <div ref={containerRef} className="prose dark:prose-invert max-w-none">{children}</div>
    </div>;
};

Each HTTP request to the service should include an authorization header that ABBYY Vantage will use to confirm your identity. Contact ABBYY to request a tenant in ABBYY Vantage service. Once you have a tenant's account, you can create user accounts. The user account's email and password can be used to get an access token for API authorization.

The OAuth 2.0 protocol is used in ABBYY Vantage for authentication. OAuth 2.0 authentication is carried out over two stages: getting an access token and then the authorization itself.

Access tokens can be obtained using two standard authentication schemes: Resource Owner Password Credentials and Authorization Code Flow.

## OpenID Connect Discovery Document

You can set up your application using OpenID Connect (OIDC) Discovery Document. For information about obtaining a tenant identifier, see the **Getting a Tenant Identifier** section of the Administrator's guide.

**Sample request:**

<VantageRegion>
  ```
  https://vantage-us.abbyy.com/auth2/TestTenant/.well-known/openid-configuration
  ```
</VantageRegion>

We also recommend using URLs found in the discovery document for ROPC and Authorization Code flows.

## Authentication Flow

<Steps>
  <Step title="Get an Access Token">
    Choose one of the two authentication methods to obtain an access token:

    * **Resource Owner Password Credentials (ROPC)** - Direct username/password authentication
    * **Authorization Code Flow** - OAuth redirect-based authentication
  </Step>

  <Step title="Include Token in Requests">
    Add the access token to the authorization header of all API requests.
  </Step>
</Steps>

## Next Steps

* [Resource Owner Password Credentials (ROPC)](/vantage/developer/authentication/resource-owner-password-credentials) - Recommended for server-to-server applications
* [Authorization Code Flow](/vantage/developer/authentication/authorization-code-flow) - Recommended for user-facing applications