Subscription (required for all Helium access)
A Helium subscription costs $50/month and is required before any Helium endpoint will respond — REST, MCP, or Slack. There is no pay-as-you-go-only path: without an active subscription, requests are rejected regardless of any credit balance on the account. Subscriptions in either theactive or past_due Stripe status count as active; a
canceled, unpaid, incomplete, trialing, or paused subscription does not.
Each successful renewal grants 6,000 credits/month into a dedicated
monthly bucket. Unused monthly credits roll over, capped at 18,000
(3x the monthly grant) — any amount still at or over that cap when the
next renewal lands is forfeited, not carried further.
How a charge is split across your two balances
Every billed Helium call spends your monthly bucket first. Only the shortfall, if your monthly bucket doesn’t cover the full price, is drawn from your persistent balance — the same non-expiring balance Horizon uses (free trial credits, prepaid packs, and Helium’s own add-on pack below). This is all-or-nothing: if the combined total across both buckets can’t cover a call’s price, nothing is charged from either one. A brand-new Helium-only signup starts with $0 in the persistent balance — unlike Horizon, it does not also receive a 1,000-credit free trial there. If you already have a Horizon account and subscribe to Helium from your dashboard, your existing persistent balance (free trial credits, packs, whatever you’ve already bought) is untouched and still usable as the fallback bucket described above.Add-on credit packs (on top of the subscription)
If you exhaust your monthly grant before your next renewal, you can buy Helium’s add-on pack any time — it isn’t gated behind waiting for your next renewal:
This lands in your persistent balance — the same shared, non-expiring
pool Horizon’s own prepaid packs use — not the resetting monthly bucket.
Buy it from the dashboard the same way you’d buy a Horizon pack; see
Horizon’s Credits & Pricing page for the
purchase flow.
Per-endpoint pricing
Charging on misses
Unlike Horizon’sperson.email (charged only on a genuine find), all
four of Helium’s billed endpoints — including find_lookalike_investors
— charge their full listed price even when the result is a clean “nothing
found” — the vendor call still happened and cost Gravity real money
either way.
No caching
Unlike several of Horizon’s endpoints, none of Helium’s research results are currently cached — everysearch_investors, enrich_investor,
research_company, or find_lookalike_investors call is a fresh live
lookup, and every response’s cached field will read false.
DELETE /v1/cache (Horizon’s cache-eviction endpoint) does not apply to
any Helium endpoint today.
Monitoring features are free for now
Reply classification, Calendar meeting-prep briefs, and LinkedIn engagement monitoring don’t debit credits at all — they’re monitoring-tier, not billed endpoints, even though some of them internally reuse the same research logic as a billed call. The only billed piece of Helium’s monitoring/ discovery features is the on-demandfind_lookalike_investors call above
— its free weekly monitoring counterpart isn’t. See
Monitoring & discovery
for the full breakdown of what runs automatically vs. on request.
This reflects today’s pricing, not a permanent commitment — any change to
the subscription price, monthly grant, rollover cap, add-on pack, or
per-endpoint costs above will be announced in advance; see the
Terms of Service for the exact
commitment.