“Reddit” is not an answer. r/selfhosted is.

The UTM row is the one worth staring at. It measures exactly the fraction of community traffic that came through a link you personally placed — which in a healthy community is the minority.

Suppose you learn that 33% of your paying customers first heard about you on Reddit. You now know one useful thing and can act on none of it: you cannot post more in “Reddit”. The decisions available to you are about specific communities — which subreddit to show up in weekly, whether r/sysadmin was ever worth the time.

So the form asks twice. Picking Reddit expands a second list in place; Hacker News does not, because there is only one Hacker News. Which channels earn the follow-up is a monthly judgment, not a fixed property — that is a config edit.

A form is one placement. Create it, then PUT the candidate list — catalog_slug pulls the label, the mark and the search aliases out of the platform catalog so you only type the things that are yours.

{
  "nodes": [
    {
      "id": "channel",
      "prompt": "Where did you first hear about us?",
      "candidates": [
        { "id": "reddit",     "catalog_slug": "reddit", "expands": "subreddit" },
        { "id": "slack",      "catalog_slug": "slack",  "expands": "slack_group" },
        { "id": "hackernews", "catalog_slug": "hackernews" },
        { "id": "discord",    "catalog_slug": "discord" },
        { "id": "github",     "catalog_slug": "github" },
        { "id": "x",          "catalog_slug": "x" },
        { "id": "google",     "catalog_slug": "google" },
        { "id": "chatgpt",    "catalog_slug": "chatgpt" },
        { "id": "friend",     "catalog_slug": "friend" },
        { "id": "dunno", "label": "I don't remember",
          "pinned": "end", "dont_remember": true }
      ]
    },
    {
      "id": "subreddit",
      "prompt": "Which subreddit?",
      "candidates": [
        { "id": "r/selfhosted", "label": "r/selfhosted" },
        { "id": "r/devops",     "label": "r/devops" },
        { "id": "r/kubernetes", "label": "r/kubernetes" },
        { "id": "r/sysadmin",   "label": "r/sysadmin" },
        { "id": "subreddit_dunno", "label": "I don't remember which",
          "pinned": "end", "dont_remember": true }
      ]
    },
    {
      "id": "slack_group",
      "prompt": "Which Slack group?",
      "candidates": [
        { "id": "slack_k8s", "label": "Kubernetes",
          "handle": "kubernetes.slack.com", "aliases": ["k8s slack"] },
        { "id": "slack_dataeng", "label": "Data Engineering",
          "handle": "dataeng.slack.com" },
        { "id": "slack_mlops", "label": "MLOps Community",
          "handle": "mlops-community.slack.com" },
        { "id": "slack_group_dunno", "label": "I don't remember which",
          "pinned": "end", "dont_remember": true }
      ]
    }
  ]
}

curl -X PUT https://www.humansurvey.co/api/attribution/forms/abc123efgh45 \
  -H "Authorization: Bearer hs_sk_..." \
  -H "Content-Type: application/json" \
  -d @channels.json
# → 200 { "id": "abc123efgh45", "version": 3, "created": true, "warnings": [] }

• Subreddit names are their own stable key. A subreddit cannot be renamed, so r/selfhosted is safe as an id. A Slack group is not — the workspace can be renamed, which is why those ids are internal (slack_k8s) and the pretty name lives in label.
• A missing community does not cost you one data point. It contaminates a neighbour: someone who found you in a Slack group and then searched picks Google, so you lose the group and book a false entry against search.
• Order is randomized per respondent by default. Options near the top get picked more often; rotating means no community sits at the top for everybody, so the raw share is unbiased.
• “I don't remember” stays visible and last. Given a list and a search box, someone who does not remember will pick something — worse than a smaller sample.

One aggregate read. There is no dashboard; the agent already in your terminal is what reads this.

curl "https://www.humansurvey.co/api/attribution/rollup\
?form_id=abc123efgh45&by=candidate&metric=revenue&from=2026-07-01&to=2026-08-01" \
  -H "Authorization: Bearer hs_sk_..."

// ILLUSTRATIVE — every figure below is invented, to show the shape of the payload
{
  "denominator": { "completed_responses": 512,
                   "per_node": { "channel": 512, "subreddit": 143, "slack_group": 61 } },
  "rows": [
    { "node_id": "channel", "candidate_id": "reddit", "label": "Reddit",
      "responses": 168, "share": 0.328,
      "revenue_cents": 1612000, "paying_responses": 151 },
    { "node_id": "subreddit", "candidate_id": "r/selfhosted", "label": "r/selfhosted",
      "responses": 71, "share": 0.497, "revenue_cents": null },
    { "node_id": "subreddit", "candidate_id": "r/devops", "label": "r/devops",
      "responses": 34, "share": 0.238, "revenue_cents": null }
  ],
  "unresolved": { "raw": 12, "dont_remember": 13, "skipped": 2, "per_node": { … } },
  "followup_unresolved": [ { "node_id": "channel", "candidate_id": "reddit",
                             "follow_node_id": "subreddit",
                             "picks": 168, "unresolved": 33, "rate": 0.196 } ]
}

The denominator ships in the payload, so the resolved rows sum to less than one and the remainder is the unresolvedblock. A reader who has to guess whether 33% already excludes the don't-knows will guess wrong, and in the direction that flatters every channel.

followup_unresolved is the number to watch in the first week: the share of Reddit picks that never resolved to a subreddit. High and steady usually means the list is missing the community people actually came from.

Run one form in the payment or upgrade flow and one in the signup flow. The payment one is where the money is: the respondent has just paid, so the answer joins to revenue with no conversion tracking at all. The signup one is the only way to see the people a community sends who never pay.

# ILLUSTRATIVE — invented figures, to show the arithmetic
# same channel, two placements, one month
                        signup form   payment form
  reddit                      0.51          0.33     ← sends volume, converts poorly
  hackernews                  0.12          0.19
  slack (Kubernetes)          0.04          0.11     ← smallest list, best rate

# reddit's share among payers / its share among signups = 0.33 / 0.51 = 0.65.
# Below 1, so reddit converts worse than your average — and the ratio is an index
# against that average, not a rate. Multiply 0.65 by your overall signup-to-paid
# rate to get reddit's own rate: at an overall 14%, reddit converts at 9.1%.
# Nothing computes it for you: it is two rollup calls and a division.

Ask early in each flow. Memory decays, and asking late means asking only the people who stayed, which systematically under-counts any community whose users churn early. A small sample is visibly small; a biased one is not.

There is no Other option — if it is not in the list, people type, and that text is stored verbatim. The most valuable thing attribution ever produces shows up here first: a community you had not thought to list.

# what people typed instead of picking, most frequent first
curl "https://www.humansurvey.co/api/attribution/forms/abc123efgh45/unresolved?limit=50" \
  -H "Authorization: Bearer hs_sk_..."
# → { "entries": [ { "node_id": "slack_group", "raw_normalized": "the k8s slack",
#                    "occurrences": 9, "variants": ["the k8s slack", "K8s Slack"] } ], … }

# map it — retroactive, so every past window moves with it
curl -X POST https://www.humansurvey.co/api/attribution/forms/abc123efgh45/remaps \
  -H "Authorization: Bearer hs_sk_..." \
  -H "Content-Type: application/json" \
  -d '{"node_id": "slack_group", "raw": "the k8s slack",
       "candidate_id": "slack_k8s"}'
# → 201 { "resolved_responses": 9, "candidate_label": "Kubernetes", "warnings": [] }

A mapping is not an edit. The rollup resolves free text against the live mapping table on every read, so one row fixes three months of history at once and revoking it moves them back.

Sign in at humansurvey.co, copy a key, and hand it to your agent. That is the whole human part.

“Set up attribution on our upgrade page. Our communities are r/selfhosted, r/devops, r/kubernetes and the Kubernetes and MLOps Slacks — ask which one when someone picks Reddit or Slack. Also list Hacker News, GitHub, X, Google, ChatGPT and word of mouth.”

Your agent reads the catalog, creates the form and hands back a URL to embed. A month later: “which communities produced revenue, and which only produced signups?”

What this is not: a place to ask your members what they thought of the AMA. There is one question here — where did you first hear about us.