AUTH V1 overview

# Step 1 — send the user here in their browser:
# https://simkl.com/oauth/authorize?response_type=code
#     &client_id=$CLIENT_ID&redirect_uri=$REDIRECT_URI
#     &app-name=my-app-name&app-version=1.0

# Step 2 — your redirect_uri receives ?code=AUTH_CODE.
# Exchange it immediately:
curl -X POST "https://api.simkl.com/oauth/token?client_id=$CLIENT_ID&app-name=my-app-name&app-version=1.0" \
  -H 'Content-Type: application/json' \
  -H 'User-Agent: my-app-name/1.0' \
  -d "{
    \"code\": \"$AUTH_CODE\",
    \"client_id\": \"$CLIENT_ID\",
    \"client_secret\": \"$CLIENT_SECRET\",
    \"redirect_uri\": \"$REDIRECT_URI\",
    \"grant_type\": \"authorization_code\"
  }"
# → { "access_token": "...", "token_type": "bearer", "scope": "public", "expires_in": 157680000 }

import AuthenticationServices

let authURL = URL(string:
  "https://simkl.com/oauth/authorize?response_type=code" +
  "&client_id=\(clientId)&redirect_uri=\(redirectURI)" +
  "&app-name=my-app-name&app-version=1.0")!

let session = ASWebAuthenticationSession(
  url: authURL,
  callbackURLScheme: "yourapp"   // matches the scheme in redirect_uri
) { callbackURL, error in
  guard let url = callbackURL,
        let code = URLComponents(url: url, resolvingAgainstBaseURL: false)?
          .queryItems?.first(where: { $0.name == "code" })?.value
  else { return }

  // POST code to https://api.simkl.com/oauth/token,
  // then store access_token in Keychain.
}
session.presentationContextProvider = self
session.start()

// build.gradle:  implementation "androidx.browser:browser:1.7.0"
import androidx.browser.customtabs.CustomTabsIntent

val authUrl = Uri.parse("https://simkl.com/oauth/authorize")
  .buildUpon()
  .appendQueryParameter("response_type", "code")
  .appendQueryParameter("client_id", BuildConfig.SIMKL_CLIENT_ID)
  .appendQueryParameter("redirect_uri", "yourapp://oauth")
  .appendQueryParameter("app-name", "my-app-name")
  .appendQueryParameter("app-version", "1.0")
  .build()

CustomTabsIntent.Builder().build().launchUrl(this, authUrl)

// Handle the redirect via an intent-filter on yourapp://oauth,
// then POST the ?code= to /oauth/token from your backend.

// In your /oauth/callback handler, after extracting `code` from the query:
const params = new URLSearchParams({
  client_id:     process.env.SIMKL_CLIENT_ID,
  'app-name':    'my-app-name',
  'app-version': '1.0',
});

const r = await fetch(`https://api.simkl.com/oauth/token?${params}`, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'User-Agent':   'my-app-name/1.0',
  },
  body: JSON.stringify({
    code,
    client_id:     process.env.SIMKL_CLIENT_ID,
    client_secret: process.env.SIMKL_CLIENT_SECRET,
    redirect_uri:  process.env.SIMKL_REDIRECT_URI,
    grant_type:    'authorization_code',
  }),
});
const { access_token } = await r.json();
// Set as httpOnly cookie or store server-side.

import requests

r = requests.post(
    'https://api.simkl.com/oauth/token',
    params={
        'client_id':   CLIENT_ID,
        'app-name':    'my-app-name',
        'app-version': '1.0',
    },
    headers={'User-Agent': 'my-app-name/1.0'},
    json={
        'code':          auth_code,
        'client_id':     CLIENT_ID,
        'client_secret': CLIENT_SECRET,
        'redirect_uri':  REDIRECT_URI,
        'grant_type':    'authorization_code',
    },
)
access_token = r.json()['access_token']

PARAMS="client_id=$CLIENT_ID&app-name=my-app-name&app-version=1.0"
UA="my-app-name/1.0"

# Step 1 — request a code:
curl "https://api.simkl.com/oauth/pin?$PARAMS" -H "User-Agent: $UA"
# → { "user_code": "ABCDE", "verification_uri": "https://simkl.com/pin/",
#     "verification_url": "https://simkl.com/pin/",
#     "expires_in": 900, "interval": 5 }

# Step 2 — show ABCDE to the user.

# Step 3 — poll every 5 seconds:
while true; do
  RESP=$(curl -s "https://api.simkl.com/oauth/pin/ABCDE?$PARAMS" -H "User-Agent: $UA")
  echo "$RESP" | grep -q access_token && { echo "$RESP"; break; }
  sleep 5
done

import requests, time

PARAMS = {
    'client_id':   CLIENT_ID,
    'app-name':    'my-app-name',
    'app-version': '1.0',
}
HEADERS = {'User-Agent': 'my-app-name/1.0'}

# 1. Request a code
pin = requests.get(
    'https://api.simkl.com/oauth/pin',
    params=PARAMS,
    headers=HEADERS,
).json()
print(f"Visit {pin['verification_uri']} and enter: {pin['user_code']}")

# 2. Poll
deadline = time.time() + pin['expires_in']
while time.time() < deadline:
    r = requests.get(
        f"https://api.simkl.com/oauth/pin/{pin['user_code']}",
        params=PARAMS,
        headers=HEADERS,
    ).json()
    if r.get('result') == 'OK' and 'access_token' in r:
        access_token = r['access_token']
        break
    time.sleep(pin['interval'])

const PARAMS  = `client_id=${CLIENT_ID}&app-name=my-app-name&app-version=1.0`;
const HEADERS = { 'User-Agent': 'my-app-name/1.0' };

// 1. Request a code
const pin = await fetch(
  `https://api.simkl.com/oauth/pin?${PARAMS}`,
  { headers: HEADERS }
).then(r => r.json());

console.log(`Visit ${pin.verification_uri} and enter: ${pin.user_code}`);

// 2. Poll
const deadline = Date.now() + pin.expires_in * 1000;
while (Date.now() < deadline) {
  const r = await fetch(
    `https://api.simkl.com/oauth/pin/${pin.user_code}?${PARAMS}`,
    { headers: HEADERS }
  ).then(r => r.json());
  if (r.access_token) { /* done */ break; }
  await new Promise(res => setTimeout(res, pin.interval * 1000));
}