Viral Score

Know whether a Reddit title or an X post will land before it goes live

One route scores both networks. With network: "reddit", reddit-pooled-v1 scores one to three titles for a subreddit: each title's chance of reaching that subreddit's top 10% of the month, what helps and hurts, the rules and the first-post penalty. With network: "x" (or no network), x-viral-v1 scores an X post draft from 0 to 100 with nine signals and two ways to improve it. Both answer at once.

Reddit: reddit-pooled-v1

Status	Live
Endpoints	POST /api/v1/viral-score
MCP tools	predict_viral_score
Scopes	viral:score
Price	$0.01 per title
Limits	20 requests a minute and 1,000 requests a day per workspace

curl -s https://app.makesmores.com/api/v1/viral-score \
  -H "Authorization: Bearer $SMORE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "network": "reddit",
    "subreddit": "running",
    "titles": [
      "First half marathon: easy miles got me under 2 hours",
      "How I paced my first half marathon"
    ],
    "post_type": "text",
    "account": "established"
  }'

Field	Rules
network	reddit
subreddit	Required, 2 to 24 characters, with or without r/
titles	Required, 1 to 3 titles of 1 to 300 characters. Each title is billed
body	Optional, up to 40,000 characters
post_type	text (default), image, video or link
flair	Optional, up to 64 characters
account	established (default) or first_post, to see the first-post penalty

The answer:

Field	Meaning
variants	One per title: title, p_top10 (0 to 1), lift (that chance as a multiple of the subreddit's base rate), pct (percentile) and rank
subreddit	name, tracked, base_rate, eligible_posts and flairs
helps, hurts	Each {label, detail}: what moved the score
rules	The posted rules with how often each is enforced (enforced, approx when estimated) and a status of ok, warn or unknown for this post
automod_held	Share of posts the subreddit's automoderator held, or null
new_account	The first-post penalty, or null when S'more has no account facts for the subreddit
wins	Formats that reach the top 10% more often
scored_at	When it was scored

The score is stored for your workspace. The same Reddit branch is what the Reddit writers run on every option.

X: x-viral-v1

Status	Live
Endpoints	POST /api/v1/viral-score
MCP tools	predict_viral_score
Scopes	viral:score
Price	$0.05 per post
Limits	10 requests a minute and 250 requests a day per workspace

curl -s https://app.makesmores.com/api/v1/viral-score \
  -H "Authorization: Bearer $SMORE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "network": "x",
    "post": "We opened our public API today. One key, every product, over REST and MCP.",
    "audience": "Developers who build agents"
  }'

Field	Rules
network	x, or leave it out
post	Required, 1 to 4,000 bytes of UTF-8
audience	Optional, up to 300 bytes

The answer:

Field	Meaning
score	0 to 100
label	The score in words
replyBait	none, possible or likely
signals	Nine signals, each {id, score, label}
improve	Two suggestions, each {signal, message}
model	x-viral-v1
xAlgorithmGuideRevision	The revision of the ranking guide the rubric follows
disclaimer	The score is S'more's estimate from a public ranking guide; X does not make it

MCP

predict_viral_score takes the same fields. Without network it scores an X post; with network: "reddit" it scores titles.

Billing

A Reddit call deducts one item per title you send and refunds any title it could not score. An X call is one post. A call that fails is refunded in full.

Errors

Status	Code	Meaning
400	invalid_request	Fields mixed between networks, a missing post or titles, or lengths out of range
409	reddit_signals_off	The Reddit branch is switched off for now
422	invalid_subreddit, subreddit_unavailable	S'more cannot score that subreddit
429	rate_limited	Over the per-minute or per-day limit
503	scoring_busy, scoring_unavailable	Try again shortly

See examples and the guide Score a post before it goes live.