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The EF.click() method records a click event and returns a Promise that resolves with the transaction ID. This transaction ID can then be used for conversion attribution.

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Basic Usage

EF.click({
  offer_id: 1,
  affiliate_id: 1
});

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Parameters

Which fields are required depends on how the click is identified — see How a click is identified below. All other fields are optional.
ParameterTypeRequiredDescription
offer_idintegerConditionalThe offer identifier — required to record a new click (direct linking)
affiliate_idintegerConditionalRequired to record a new click — unless the affiliate is supplied by a coupon_code, or an existing click is matched via transaction_id
uidintegerNoOffer URL ID (extra destination URL)
creative_idintegerNoCreative identifier
sub1 – sub10stringNoAffiliate sub-placement tracking values
adv1 – adv10stringNoAdvertiser sub-parameter values
source_idstringNoTraffic source identifier
coupon_codestringConditionalA coupon code — records a click attributed via the coupon’s offer and affiliate
costnumberNoMedia-buying cost to attribute to this click
fbclidstringNoFacebook click ID (auto-detected from the URL if omitted)
gclidstringNoGoogle click ID (auto-detected from the URL if omitted)
ttclidstringNoTikTok click ID (auto-detected from the URL if omitted)
sccidstringNoSnapchat click ID (auto-detected from the URL if omitted)
transaction_idstringConditionalA 32-character transaction ID — matches an existing click instead of creating one (ITP workaround)
tracking_domainstringNoTracking domain override (for multi-tenant setups — see Configuration)
parametersobjectNoFree-form custom key–value parameters
do_not_trackbooleanNoWhen true, the call resolves immediately without recording a click

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How a click is identified

EF.click() resolves to one of three behaviors depending on which identifier you pass. Provide the fields for the mode you need:
  • New click (direct linking) — requires both offer_id and an affiliate identity (affiliate_id). If either is missing, the server records the click with an error code and returns no transaction ID — the promise resolves with an empty string. This is what most recipes do.
  • Existing click (ITP workaround) — pass a valid 32-character transaction_id (typically read from _ef_transaction_id after a redirect tracking link). The SDK matches the click that already exists and reinforces its first-party cookie; offer_id and affiliate_id are not needed and are ignored in this mode. If the ID is missing, malformed, or not found, the call falls back to recording a new click — which then requires offer_id.
  • Coupon attribution — pass coupon_code; the offer and affiliate are resolved from the coupon assignment.
The 32-character length matters: a transaction_id that isn’t exactly 32 characters is treated as absent, and the call falls through to new-click behavior.
Coupon code takes precedence. If a valid coupon_code arrives alongside offer_id and affiliate_id, the click is attributed to the coupon’s offer and affiliate — not the passed affiliate_id. Only send a coupon_code when you intend coupon-based attribution.

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Return Value

EF.click() returns a Promise that resolves with the transaction ID: 
EF.click({
  offer_id: 1,
  affiliate_id: 1
}).then(function(transactionId) {
  console.log('Transaction ID:', transactionId);
});
The promise always resolves and never rejects. On success it resolves with the 32-character transaction ID; when nothing could be tracked — do_not_track, no valid identifier, or a server/validation error — it resolves with an empty string instead. This is why patterns that chain off the result (cross-site link decoration, the EF-to-EF chain) test if (transactionId) and supply a fallback rather than relying on .catch().

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Examples

With sub-placements and URL parameters: 
EF.click({
  offer_id: EF.urlParameter('oid'),
  affiliate_id: EF.urlParameter('affid'),
  sub1: EF.urlParameter('sub1'),
  sub2: EF.urlParameter('sub2'),
  source_id: EF.urlParameter('source')
});
EF.urlParameter() returns null when the parameter is not present in the URL. The SDK skips any optional field whose value is null or undefined, so a missing URL parameter is simply omitted from the click rather than sent as an empty value.
Parameters after a # in the URL are not readable. EF.urlParameter() reads from the URL’s query string (?…), so anything in the fragment — e.g. https://example.com/#/path?oid=1&affid=2 — is invisible to it, and the click will be missing those values. This is common with hash-routed single-page apps. If your parameters live after the #, move them before it, or read them from window.location.href directly instead of EF.urlParameter().
With custom parameters: 
EF.click({
  offer_id: 1,
  affiliate_id: 1,
  parameters: {
    campaign_name: 'summer_sale',
    landing_page: 'variant_b'
  }
});
All parameters: A reference call listing every parameter EF.click() accepts. In practice you only pass the ones relevant to your setup — optional fields with a null/undefined value are omitted automatically. 
EF.click({
  // Core attribution — provide at least one of offer_id, transaction_id, or coupon_code
  offer_id: EF.urlParameter('oid'),
  affiliate_id: EF.urlParameter('affid'),
  transaction_id: EF.urlParameter('_ef_transaction_id'),
  coupon_code: EF.urlParameter('__cc'),

  // Optional attribution context
  uid: EF.urlParameter('uid'),
  creative_id: EF.urlParameter('creative_id'),
  source_id: EF.urlParameter('source_id'),

  // Affiliate sub-parameters (sub1–sub10)
  sub1: EF.urlParameter('sub1'),
  sub2: EF.urlParameter('sub2'),
  sub3: EF.urlParameter('sub3'),
  sub4: EF.urlParameter('sub4'),
  sub5: EF.urlParameter('sub5'),
  sub6: EF.urlParameter('sub6'),
  sub7: EF.urlParameter('sub7'),
  sub8: EF.urlParameter('sub8'),
  sub9: EF.urlParameter('sub9'),
  sub10: EF.urlParameter('sub10'),

  // Advertiser sub-parameters (adv1–adv10)
  adv1: EF.urlParameter('adv1'),
  adv2: EF.urlParameter('adv2'),
  adv3: EF.urlParameter('adv3'),
  adv4: EF.urlParameter('adv4'),
  adv5: EF.urlParameter('adv5'),
  adv6: EF.urlParameter('adv6'),
  adv7: EF.urlParameter('adv7'),
  adv8: EF.urlParameter('adv8'),
  adv9: EF.urlParameter('adv9'),
  adv10: EF.urlParameter('adv10'),

  // Media-buying cost
  cost: EF.urlParameter('cost'),

  // Paid-channel click IDs (auto-detected from the URL if omitted)
  fbclid: EF.urlParameter('fbclid'),
  gclid: EF.urlParameter('gclid'),
  ttclid: EF.urlParameter('ttclid'),
  sccid: EF.urlParameter('sccid'),

  // Route this click to a specific Everflow account (overrides the SDK script's domain)
  tracking_domain: 'www.your-tracking-domain.com',

  // Free-form custom query parameters
  parameters: {
    my_custom_key: 'my_custom_value'
  },

  // Behavior flag
  do_not_track: false
});
You can combine the SDK with traditional redirect tracking links to enhance attribution on browsers that restrict third-party cookies (Safari ITP, etc.). When a user lands on your owned landing page after going through a redirect link, fire EF.click() with the transaction_id extracted from the URL — the SDK will set a first-party cookie on your landing-page domain, making subsequent conversion attribution more reliable. Configure your tracking link’s destination URL to include the transaction_id, offer_id, and affiliate_id macros. For a destination URL like: 
https://destination-url.com?transaction_id=af189e77650e4e908af797b61b03ac0b&oid=1&affid=5
fire the SDK click with the extracted values: 
EF.click({
  offer_id: EF.urlParameter('oid'),
  affiliate_id: EF.urlParameter('affid'),
  transaction_id: EF.urlParameter('transaction_id')
});
The SDK recognizes the existing transaction_id and enhances attribution without creating a duplicate click.

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Advanced Usage

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Preventing duplicate clicks

Use EF.getTransactionId() to check whether a transaction already exists for the offer before firing a new click — useful when the same page may be loaded multiple times for a returning user: 
var offerId = 3;
var previousTransactionId = EF.getTransactionId(offerId);

if (!previousTransactionId) {
  EF.click({
    offer_id: offerId,
    affiliate_id: EF.urlParameter('affid')
  });
} else {
  // The user already has a transaction for this offer — skip firing a new click
}

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Falling back to default values

When the URL may not always contain offer_id or affiliate_id parameters, you can supply default values rather than letting the click fail: 
var DEFAULT_OFFER_ID = 1;
var DEFAULT_AFFILIATE_ID = 10;

var offerId = EF.urlParameter('oid') || DEFAULT_OFFER_ID;
var affiliateId = EF.urlParameter('affid') || DEFAULT_AFFILIATE_ID;

EF.click({
  offer_id: offerId,
  affiliate_id: affiliateId
});
For fleet-wide organic fallback (applied automatically to every SDK call on the page), use EF.configure({ organic: {...} }) instead of per-call defaults.

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Multi-tenant attribution (multiple Everflow accounts)

When multiple Everflow accounts fire clicks on the same page, pass tracking_domain per call to route each click to the correct account. See Multi-account tracking for the full pattern and caveats.