The 30-second summary
RANDOM.ORG's paid API upgrades the free service in two important ways: higher quotas, and signed responses (the "Signed API"). A signed response carries RANDOM.ORG's digital signature over the result, so the verifier knows it came from RANDOM.ORG.
Provable.io uses a different trust model: instead of "trust this signature came from us," it's "re-derive the value yourself from the published seed." Both are legitimate; the right pick depends on whether your verifier wants to trust an operator key or compute the result themselves.
Feature matrix
| Capability | Provable.io | RANDOM.ORG (paid Signed API) |
|---|---|---|
| Trust model | Re-derive value from published seed + hash | Operator-signed response (trust RANDOM.ORG's key) |
| Entropy source | HMAC-SHA256 over committed seeds | Atmospheric noise (hardware) |
| Open-source generator | Yes — provable-core | No — proprietary backend |
| Pricing | Free up to per-account daily quota | Paid plans by bits / signed requests |
| Pre-commitment | Yes — serverHash published first | Implicit (signed at time of response) |
| Reproducible from seed | Yes | No — fresh entropy each call |
| Game primitives | dice, shuffle, weighted pick, bytes, distributions | integers, sequences, strings, gaussians, signed variants |
| Latency | ~tens of ms | ~tens of ms |
| Best for | Public-audience draws auditable from first principles | Buyers who want a hardware-entropy origin + operator signature |
When RANDOM.ORG's paid API is the right answer
RANDOM.ORG has been a respected operator since 1998, and the Signed API is genuinely useful when:
- Your auditor or jurisdiction specifically wants hardware-sourced entropy. Some compliance regimes anchor to physical entropy sources.
- You want a third-party signature over the result and you're happy to trust RANDOM.ORG's key.
- You need very large draws beyond the free tier and budget isn't a blocker.
When Provable.io is the right answer
A trust-the-operator-key model is the right shape for some buyers; an open-derivation model is the right shape for others. Pick Provable.io when:
- You want verification that doesn't require trusting an operator key. Anyone with the open-source verifier and the seeds can re-derive.
- You're cost-sensitive. The free tier is generous; signed responses cost nothing extra.
- You need richer primitives — dice notation, weighted pick, shuffle, distributions. See dice & coins and weighted loot.
Try it now
A draw the verifier can re-derive themselves — no operator signature required.
curl "https://api.provable.io/api/ints?clientSeed=vs-random-org-paid&count=5&min=1&max=100"FAQ
Is a signed response weaker than seed re-derivation?
Not weaker — different. A signature compresses trust into one key; re-derivation distributes it across the open-source verifier. Some audit programs prefer the signature, some prefer the recomputation. Both are sound.
Can I use both?
Yes. A common pattern: source the clientSeed from RANDOM.ORG's signed bits, then call Provable.io. You get hardware entropy and public verifiability.
See the free-tier comparison?
Yes — see Provable.io vs Random.org.