Proof Holdings vs SIWE
SIWE (ERC-4361) is the open standard for proving control of a wallet a user already owns — the verify-don't-provision idea, done right and free. Proof Holdings productizes that same idea across assets with a portable proof token and a managed API. Wallet verification is coming soon; the model is live today for phone, email, and domain.
SIWE is the right standard when you want to build; Proof is the same philosophy when you'd rather call one API. Verify-don't-provision across every asset, one flat price, a portable ES256 token every time — live today for phone, email, and domain.
One API · One key
One key does what a stack of vendors does
Most platforms on this page run wallet infrastructure. Proof — like SIWE — never touches a key: a single API whose reverse-OTP flow issues a signed, offline-verifiable ES256 token for each of these:
Flat price · Any asset
One flat price for every asset — phone, email, and domain today, with wallet and social coming soon. No per-seat, no per-MAU, no per-verification tiers — the meter that makes every rival's bill jump.
- Free every month
- 300 proofs
- Pay as you go
- €0.03 / proof
- At volume
- €0.0079 / proof
Feature Comparison
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| Feature | Proof Holdings | SIWE (Sign-In with Ethereum) |
|---|---|---|
| What it is | Managed verification API (any asset) | Open standard (ERC-4361), build it yourself |
| Verify a wallet the user already owns | Coming soon (8 chains planned) | Yes |
| Provisions / custodies wallets | No | No |
| Also verifies phone / email / domain | Live today | No |
| Output | Portable ES256 proof token | Signed message — you build the token layer |
| Chains | 8 planned (ETH, SOL, BTC, BNB, Cosmos, Tron, ADA, Hedera) | EVM only (non-EVM via CAIP-122, still draft) |
| Smart-contract wallets | Planned | EIP-1271 needs an on-chain call (not offline) |
| Managed service / SLA / support | Yes | No |
| Cost | Per-proof (€0.0079) | Free (open standard) — you host verification |
Pricing
Cost
Proof Holdings
€0.0079/proof, 300 free/month, managed
SIWE (Sign-In with Ethereum)
Free — open standard, you build and host it
Build vs buy
Proof Holdings
One API call — verification + token + multi-asset
SIWE (Sign-In with Ethereum)
You implement verification, session, token, and multi-chain
Self-sovereign & open
Proof Holdings
Proprietary API (with a portable, standard token)
SIWE (Sign-In with Ethereum)
Fully open, no vendor, community libraries
Wallet verification today
Proof Holdings
Coming soon — live for phone/email/domain now
SIWE (Sign-In with Ethereum)
Live today (EVM)
Same philosophy — verify, don't provision
SIWE and Proof Holdings start from the same, correct premise: you verify a wallet (or asset) the user already controls; you don't create one for them. SIWE has the user sign a structured message with their existing wallet — no custody, no key management, no new account. That's exactly Proof's model too, extended beyond wallets to phones, emails, and domains.
The difference is build vs buy. SIWE is an open standard (ERC-4361) and a great one — free, self-sovereign, EVM-native, with a large library ecosystem. But it hands you a signed message, not a token: you build the session layer, the token issuance, the multi-chain handling, and the smart-contract-wallet case (EIP-1271, which needs an on-chain call) yourself. Proof productizes the whole thing behind one API and returns a portable ES256 proof token — with wallet verification coming soon, and the same flow already live for phone, email, and domain.
One asset, or every asset
SIWE is, by name and by spec, about Ethereum wallets — the base standard is EVM-only, and the chain-agnostic generalization (CAIP-122 / SIWx, covering Solana and others) is still a draft. If your world is EVM and you're happy to build, SIWE is hard to beat on openness.
Proof Holdings is asset- and chain-agnostic by design: the same reverse-verification flow that today proves control of a phone, email, or domain is being extended to wallets across eight planned chains, all returning the same signed token. If you want one verification primitive across assets — with a managed API instead of a DIY standard — that's the trade Proof offers. If you want the open standard and control every layer yourself, that's SIWE.
When to use SIWE (Sign-In with Ethereum)
- You're EVM-only and happy to implement wallet verification yourself
- You want a fully open, vendor-free standard with community libraries
- You already have session/token infrastructure and just need the signature step
- Self-sovereignty and zero vendor dependency matter more than a managed service
- You want the lowest possible cost and don't need multi-asset or support
When to use Proof Holdings
- You want a managed API, not a standard to implement and host
- You want one verification primitive across phone, email, domain — and wallet (soon)
- You want a portable proof token out of the box, not just a signed message
- You'd rather not build the token, session, and smart-contract-wallet layers
- You want multi-chain wallet coverage on a roadmap rather than EVM-only today
- You want an SLA and support behind the verification step
Frequently Asked Questions
Ready to try Proof Holdings?
300 free proofs per month. No credit card required.
Building with an AI agent? The 176-tool MCP server and test mode let an agent run a real verification right now — machine quickstart in llms-full.txt.