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Reddit offers self-serve Ads signup and a public server-side Conversions API. Use the Pixel and CAPI together. Use one conversion ID across both paths.

Account and access

1. Open Reddit Ads and select Get started. Set up a business and advertiser account.
2. For an existing business, ask its owner to add you as a creator or administrator. Reddit documents both paths in its CAPI direct integration guide.
3. In the correct business, open Events Manager. Select Configure data source → Conversions API → Set up manually. Select Conversions API Only if the Pixel does not exist.
4. Copy the Pixel ID. Select Generate Access Token, name and generate it, then copy it. Reddit says it cannot retrieve this token later. Reddit recommends this non-expiring conversion token in its CAPI guide.

This direct CAPI path does not require a Developer Portal OAuth app. Use that separate OAuth credential for other Ads API work. The API uses a bearer token with adsconversions; see Reddit API authentication.

Use these application names. They follow ad-conversion-hub. Reddit does not define the environment variable names.

REDDIT_PIXEL_ID    public Pixel identifier
REDDIT_CAPI_TOKEN  server-only Conversion Access Token

The Pixel must belong to the same business account as the events. See About the Reddit Pixel.

Client-side Pixel

Load the official script on every page that can begin attribution, before event calls. Reddit documents manual, GTM, Shopify, and partner installs in About the Reddit Pixel.

<script>
!function(w,d){if(!w.rdt){var p=w.rdt=function(){p.sendEvent?p.sendEvent.apply(p,arguments):p.callQueue.push(arguments)};p.callQueue=[];var t=d.createElement("script");t.src="https://www.redditstatic.com/ads/pixel.js";t.async=!0;var s=d.getElementsByTagName("script")[0];s.parentNode.insertBefore(t,s)}}(window,document);
rdt('init', '<REDDIT_PIXEL_ID>');
rdt('track', 'PageVisit');
</script>

Fire the conversion on the page where the action completes. For a purchase, use the payment transaction ID as the deduplication value.

rdt('track', 'Purchase', { value: 25, currency: 'USD', conversionId: '<canonical-event-id>' });

The client field is conversionId. The CAPI field is metadata.conversion_id. Keep the value identical. Do not use a page-load timestamp. Reddit also supports an Event Setup Tool, GTM, Shopify, and partner integrations. Use one client implementation, or share the same ID.

Canonical event mapping

The hub owns the canonical name. This adapter owns Reddit's spelling. See Reddit's standard event list.

Custom names are case-sensitive, can use up to 64 UTF-8 characters, and must not match standard events. Only the 20 most recent show in the dashboard. See CAPI direct integration.

Server-side Conversions API v3

Send from the backend after the business action succeeds. For purchases, use the payment provider webhook. See Post Conversion Events.

POST https://ads-api.reddit.com/api/v3/pixels/{pixel_id}/conversion_events
Authorization: Bearer <REDDIT_CAPI_TOKEN>
Content-Type: application/json

The v3 body has a data object. A top-level events array is a v2 mistake.

{
  "data": { "events": [{
    "event_at": 1700000000000,
    "action_source": "WEBSITE",
    "event_source_url": "https://example.com/thanks?rdt_cid=...",
    "click_id": "<rdt_cid>",
    "type": { "tracking_type": "PURCHASE" },
    "metadata": {
      "conversion_id": "<canonical-event-id>",
      "currency": "USD", "value": 25, "item_count": 1,
      "products": [{"id": "plan_pro", "name": "Pro", "quantity": 1, "item_price": 25}]
    },
    "user": {
      "email": "<sha256-reddit-email>",
      "external_id": "<sha256-stable-user-id>",
      "ip_address": "<client-ip>", "user_agent": "<client-user-agent>",
      "uuid": "<first-party-_rdt_uuid>"
    }
  }]}
}

Required fields are event_at, action_source, and type.tracking_type. event_at uses Unix epoch milliseconds. Use WEBSITE for web events, and up to 1,000 events per request. Send revenue value, ISO 4217 currency, and item_count; Reddit strongly recommends them for revenue optimization.

event_source_url is recommended for WEBSITE events. Reddit uses it for domain detection and can extract rdt_cid if click_id is missing. A valid response contains Successfully processed N conversion events.

Identity and consent

The hub gates dispatch. Require measurement: true before any event and ad_user_data: true before email, phone, or external IDs. Do not reject an event only because it has no click ID. Follow the hub consent and adapter contract.

This adapter sends hashed identity only. Reddit's match-key and hashing rules are:

• Email: lowercase it. Remove local-part dots and the plus suffix. SHA-256 it to 64 lowercase hex digits.
• Phone: normalize to E.164. Include country and area code. Remove the extension and non-numeric characters. Ensure +, then SHA-256 it.
• External ID: use a stable user ID and SHA-256 it. Send IP, user agent, and UUID as documented. Do not hash them.

Do not hash an identifier twice. If measurement is allowed but behavioral targeting is not, send LDU. LDU is the only mode; country is required and region is optional.

"data_processing_options": {
  "modes": ["LDU"], "country": "US", "region": "US-CA"
}

LDU does not replace the hub's measurement consent gate.

Deduplication

Use one ID for the client and server copies:

• Pixel: conversionId.
• CAPI: metadata.conversion_id.

Reddit matches the same event type and channel. Pixel events deduplicate against CAPI WEBSITE events, not different channels. It prefers more metadata and match keys. Events should arrive within two days; the record stays for up to seven days. See Reddit's deduplication rules.

Without a conversion ID, session deduplication needs the same UUID or external ID on both events. Use the explicit conversion ID path for purchases.

Click ID persistence

Reddit appends rdt_cid to the landing URL. Capture it on first landing and preserve it through redirects, signup, and checkout. Reddit documents a first-party cookie, browser storage, or server session; use a server session when possible. See Click ID persistence.

Reddit does not document a native rdt_cid expiration. Retain it for the selected window. The default is 28-day click-through and one-day view-through. Click windows are 1, 7, or 28 days. View-through cannot exceed click-through. Check Events Manager → Attribution Settings. See Web Attribution.

CAPI events must be sent within seven days. This is separate from attribution. Do not gate a server event on rdt_cid; click_id is optional.

Tracking quirks that cause failures

• v2 payloads fail in v3. Use data.events, type.tracking_type, and metadata.
• Test Events is limited. Put test_id inside data. Only one event per request appears, and it can take five seconds. Remove test_id in production. See Verify Conversion Events.
• Pixel tests need third-party cookies. Use the Reddit Pixel Helper if the Events Manager test view is empty.
• Attribution settings alter totals. An accepted event can receive no ad credit outside the active attribution window.
• LDU needs a country. modes: ["LDU"] without country is invalid.
• Campaign setup needs a Pixel. Since July 13, 2026, new ad groups and CBO campaigns require conversion_pixel_id; see the v3 change history.
• Reports settle slowly. Metrics can take up to six hours to stabilize; see Get A Report.

Secrets: don't assume process.env is populated at request time

Some app setups bake environment variables into a generated module at build time rather than reading process.env directly at runtime (common on serverless/edge platforms where the runtime environment isn't guaranteed to match the build environment). If your pixel/token reads come back empty in production despite being set somewhere in your deploy config, check whether your app has a build-time secret-generation step (grep for wherever your other, working analytics secrets — e.g. a GA4 API secret — are imported from) and match that pattern, rather than assuming a direct process.env.YOUR_VAR read will work. This exact mismatch silently no-ops a CAPI integration with no error — the code runs, the if (!token) return guard just always takes the empty-token branch.

No email-match audience product (no lookalike here)

Reddit's custom audiences are retargeting / device-id (MAID) based — there's no hashed-email upload, so you can't seed a lookalike from your own user list the way Meta (Custom Audience → Lookalike) or Google (Customer Match) let you. Don't mistake the custom-audience endpoints for an email-match product — for lookalike/seed-audience experiments, use Meta or Google and skip Reddit. See ad-experiments.

Verification

Use request proof, platform proof, and business proof:

1. Require a 2xx response. Do not treat it as platform proof.
2. In Events Manager → Event Testing, create a test ID. Send one event and check its Pixel ID, event name, conversion ID, match keys, and metadata.
3. Call the server-side Get Last Fired At endpoint with the same token:

GET https://ads-api.reddit.com/api/v3/pixels/{pixel_id}/last_fired_at
Authorization: Bearer <REDDIT_CAPI_TOKEN>

The response gives the latest ISO 8601 time for standard and custom events. Use Get A Report for attributed counts. Reconcile purchases with the payment provider. Reddit is not the payment ledger.

Common pitfalls

• Using a Developer Portal OAuth token instead of a Conversion Access Token.
• Sending a v2 top-level events array to the v3 endpoint.
• Putting event_id or conversion_id at the wrong level.
• Using SignUp or SIGNUP instead of Sign Up and SIGN_UP.
• Reusing one conversion ID for several events.
• Losing rdt_cid during a redirect or checkout handoff.
• Sending different event types or channels from Pixel and CAPI.
• Sending raw identity or logging request bodies.
• Letting a Reddit timeout fail a payment webhook. Apply the hub retry policy.

Security

Keep REDDIT_CAPI_TOKEN in the deployment secret store. Never put it in a browser bundle, URL, log, screenshot, or pull request. Load the Pixel only from https://www.redditstatic.com/ads/pixel.js over HTTPS. Restrict raw identity access. Record consent. Delete temporary normalized values after dispatch.