The only Bitcoin loan product where your collateral stays in a script you can verify on-chain. Taproot vault, unilateral exit, zero rehypothecation. Early stage, audits pending.
Surge Credit launched mainnet public beta in April 2026. Smart contract and Taproot script audits are in progress (reardencode on the Bitcoin side, EVM auditor in selection). We list it because the custody model is genuinely differentiated, not because the product is battle-tested. Do your own diligence before committing meaningful capital.
Three of the biggest names in Bitcoin-backed lending went bankrupt between 2022 and 2023. Celsius, BlockFi, Voyager. Customers handed over Bitcoin expecting to get it back. They did not. The mechanism was always the same: pooled custody, rehypothecation, and an unsecured-creditor outcome when the music stopped.
Surge Credit answers that question differently. Your Bitcoin never leaves the Bitcoin blockchain and never sits under anyone's discretionary control. Collateral locks into a Taproot vault on Bitcoin mainnet, governed by a script with three explicit spending paths: cooperative repayment, automated liquidation if your LTV breaches the threshold, and a unilateral exit by you after a roughly one-year timelock. The key-path spend is mathematically disabled using a NUMS internal key, which means even Surge cannot bypass the rules.
The credit logic, which covers interest, debt accounting, and Dutch auction liquidation, runs on Base, Coinbase's Ethereum L2. You receive USDC, routed cross-chain via Circle's CCTP v2. Rates start at 6.9% variable, 9.9% fixed. No origination fees. $5 minimum. No KYC. If your priority is custody and not being a counterparty in the next CeFi blow-up, this is the most principled product on this page. If you need fiat in your bank account next week or want a battle-tested platform, it is not yet the right choice.
| Category | Score | Notes |
|---|---|---|
| Custody Model | 10/10 | Non-custodial Taproot vault with NUMS-disabled key-path. Best in class. |
| Transparency | 9/10 | On-chain collateral, public ledger at earn.surge.credit, open-source exit tool. |
| Audit Status | 5/10 | Both audits in progress at publication. Score will move when reports are public. |
| Rate Transparency | 8/10 | Clear variable / fixed split, no origination fees, no hidden costs. |
| Track Record | 5/10 | Mainnet public beta since April 2026. No production liquidations yet. |
| Fiat Off-Ramp | 6/10 | USDC only today. Bank and card off-ramp on roadmap but deprioritized. |
| Overall | 7.5/10 | Most principled custody model on the page. Score gated by early-stage status. |
| Spec | Details |
|---|---|
| Product Type | Bitcoin-backed dollar credit line (non-custodial) |
| APR | From 6.9% variable (2% to 18% range) / 9.9% fixed |
| Max LTV | 50% (planned 75% with direct protocol integrations) |
| Origination Fees | None |
| Minimum Loan | $5 |
| Term | 12 months, rollover anytime |
| Repayment | Repay any amount, anytime |
| Custody Model | Non-custodial Taproot vault (NUMS-disabled key-path) |
| Rehypothecation | No (structurally impossible, verifiable on-chain) |
| KYC Required | No (permissionless protocol) |
| Disbursement Asset | USDC (bank/card on roadmap, not prioritized) |
| Settlement | Bitcoin (collateral) + Base L2 (credit engine, USDC via CCTP v2) |
| Funding Speed | ~30 minutes after BTC confirmation |
| Apps | iOS (blocked only in China), Android (global) |
| Mainnet Status | Public beta since April 2026 |
| BTC Locked (at review) | 8.8 BTC |
| Active Borrowers | 27 beta + 97 legacy private beta |
| Oldest Open Position | 150 days |
| Production Liquidations | None to date |
| Audit Status | Taproot + DCN: reardencode (Brandon Black, BIP-349 co-author). EVM auditor in selection. |
| Governance | Two-entity model (Amby Inc + Surge Foundation in formation) |
When you deposit BTC into a Surge vault, you are not sending it to a wallet. You are sending it to a Bitcoin output that can only be spent through one of three explicit conditions written into Bitcoin script and enforced by the entire network.
Door 1, cooperative repayment. You repay your USDC debt on Base. The Distributed Custody Network co-signs a transaction that releases your BTC back to your withdrawal address. This is how almost every loan should end.
Door 2, automated liquidation. Your collateral ratio breaches the liquidation threshold (or the 12-month term expires unpaid). The DCN signs a sweep of your collateral into a Dutch auction on Base. Proceeds retire the debt. Liquidation is partial: any surplus BTC re-locks into a new vault under the same scripts.
Door 3, unilateral exit. If Surge disappears, you can spend the exit leaf yourself after a relative timelock of roughly one year. No coordination with Surge required. The exit tooling is open-source. This is the difference between "trust us" and "verify us."
There is technically a fourth path on every Taproot output, the key-path spend. On Surge vaults, the key-path is built from a NUMS (Nothing Up My Sleeve) internal key derived from the SHA-256 hash of the string "SURGE-NUMS." Nobody knows the private key because nobody can. The practical effect: the DCN cannot bypass the three script paths, even by collusion. To learn the concept in more depth, see our Taproot vaults explainer.
The lender-side signatures are produced by Surge's Distributed Custody Network (DCN), a set of independent signers running threshold signature ceremonies based on Lindell 2024 (a threshold Schnorr scheme). The current threshold is a simple majority.
Lindell 2024 was chosen for a specific property called identifiable abort. If a signer misbehaves during the signing process, the protocol produces cryptographic evidence of who misbehaved. That matters because future versions can slash misbehaving signers economically.
This is the weakest part of the trust story today. The DCN signer organizations have not been publicly announced (Surge has indicated a June 2026 announcement). Until names are public and external observers can verify independence, your trust assumption is "the DCN's majority will behave correctly during the next twelve months" rather than "this is a credibly decentralized network."
Variable rate. Starts at 6.9%, moves between 2% and 18% based on pool utilization. Surge has seen 80 to 95% utilization since mainnet launch, which puts borrowers in the 4.5 to 8% range. Interest accrues continuously on your outstanding balance.
Fixed rate. 9.9% locked. You pay more than current variable in exchange for certainty against utilization spikes.
LTV. Capped at 50% today, planned to move to 75% with direct protocol integrations. At a $100,000 BTC price, 1 BTC of collateral lets you draw up to $50,000 USDC.
Term and repayment. 12-month term that rolls over automatically. Repay any amount, any time. No penalty for early repayment, no fixed schedule, no minimum monthly payment.
Fees. Zero origination. Zero account fees. You pay the interest, the on-chain Bitcoin fee to fund and unwind the vault, and Base gas fees for the EVM-side operations.
We have not yet run the full borrow flow on mainnet ourselves. When we do, this section will cover wallet setup, vault address generation, BTC deposit confirmation time, USDC arrival time, partial and full repayment tests, BTC recovery time, total elapsed time, and any friction points, with screenshots.
Until then, the documented user-facing flow is: install the Surge App (iOS or Android), generate a vault address, deposit BTC, wait for confirmation, draw USDC up to your LTV cap, repay any amount any time, and recover your BTC through the cooperative-repayment path. Funding shows up approximately 30 minutes after collateral confirms on Bitcoin.
These four products cover the realistic spectrum of Bitcoin-backed lending in 2026: fully non-custodial Taproot vault (Surge), traditional custodial with optional segregated tier (Ledn), custodial integrated with a payments platform (Strike), and non-custodial P2P multisig (Hodl Hodl).
| Feature | Surge Credit | Ledn | Strike | Hodl Hodl |
|---|---|---|---|---|
| Custody | Non-custodial Taproot vault | Custodial / segregated option | Custodial | You co-hold a key (3-of-4) |
| Rehypothecation | No (verifiable on-chain) | No on segregated tier | No (contract) | No (structural) |
| KYC | No | Yes | Yes | Varies by offer |
| Min loan | $5 | $500 | $10,000 | Varies |
| APR (typical) | 4.5% to 9.9% | 10.9% to 12.4% | ~9.5% | 8% to 15% |
| Fiat off-ramp | No (USDC only) | Yes | Yes | Indirect |
| Track record | Public beta (April 2026) | Since 2018, $7B+ loans | Established | Since 2018 |
| Audit posture (Bitcoin side) | reardencode (pending) | Internal | Internal | Public (multisig is verifiable) |
Surge wins on custody and KYC. Strike wins on speed and price for established platforms. Ledn wins on track record and fiat off-ramp. Hodl Hodl wins on multisig collaborative custody with the longest non-custodial operating history. Pick by which constraint dominates your situation.
Taproot scripts and Distributed Custody Network. Audited by Brandon Black (reardencode), co-author of BIP-349 (OP_INTERNALKEY), former Taproot wallet engineer at BitGo, former Casa. Findings expected end Q2 2026 followed by a remediation period before public release. We will summarize the report here once it is public.
EVM smart contracts. Auditor in selection at the time of this review. Engagement expected to be signed within weeks of publication. We will summarize findings once that report is also public.
The audit choice on the Bitcoin side is genuinely serious. reardencode is a Bitcoin-specific specialist with upstream protocol contributions, not a generic crypto auditor. The EVM auditor choice will tell us how seriously the EVM side is being treated.
The end-state design is a two-entity model similar to Aave and Morpho. The Surge Foundation, a non-profit legal entity in formation at publication, holds the upgrade rights and the canonical implementation. Amby, Inc. (the for-profit company) builds the software and licenses it to the foundation. Deployed contracts are immutable; upgrades require governance approval.
Until the foundation is live and the upgrade keys move over, governance is effectively concentrated in Amby Inc. That is a meaningful trust-minimization gap that has not closed yet. Surge expects the entity to be formally registered within three weeks of May 2026 with an additional handover period after that.
The DCN is the other half. Today it operates with a simple-majority threshold across a small set of signers whose names are not yet public. Once names are published (planned June 2026) and independence can be verified externally, the trust story becomes much stronger.
Surge Credit is the most principled non-custodial Bitcoin lending product available right now. The architecture is genuine, the audit choice is serious, the team is identifiable and accessible, and the failure modes are documented and addressable through the unilateral exit path. If you have spent the last four years watching Bitcoin lenders blow up, this is the first product that addresses the root cause instead of asking you to trust a new set of operators.
It is also early-stage software with an incomplete decentralization story, a pending audit cycle, no battle-tested liquidations, and a USDC-only output that creates real friction for non-US users. The 7.5/10 reflects that: ceiling raised by an exceptional custody model, floor anchored by short operating history.
If your loan size is in the "I would not lose sleep if it vanished" range, Surge is worth using to learn the system. If you are borrowing against a meaningful percentage of your stack, we recommend waiting for the audits to land and the Surge Foundation to formalize. For established alternatives today, see Hodl Hodl / Debifi for non-custodial multisig, or Strike Loans for low-cost custodial.
$5 minimum, no KYC, your collateral verifiable on-chain. Read the docs, check the public ledger, then decide.
Surge Credit is a Bitcoin-backed dollar credit line that does not custody your Bitcoin. Where Strike, Nexo, Ledn and most other Bitcoin lenders hold your BTC in pooled custody and ask you to trust them with it, Surge locks your collateral into a Taproot vault on the Bitcoin blockchain. The vault is controlled by a script with three possible spending paths (cooperative repayment, automated liquidation, or a unilateral exit by you after a one-year timelock) and the key-path spend is mathematically disabled. Even Surge cannot move your coins outside those three rules. The credit accounting runs on Base (an Ethereum L2) and you receive USDC, but the actual Bitcoin never leaves a script you can verify on-chain.
Both audits are in progress at the time of this review. The Taproot script and Distributed Custody Network are being audited by Brandon Black (reardencode), co-author of BIP-349 (OP_INTERNALKEY) and former Taproot wallet engineer at BitGo. The EVM smart contract auditor is in selection. We will update this review with the findings once both reports are public. Until then: Surge has been on mainnet public beta since April 2026 with 8.8 BTC locked across 124 borrowers and zero production liquidations. Custody is verifiable on-chain via earn.surge.credit and positions.surge.credit. Treat it as early-stage software, not a battle-tested platform.
You can recover it yourself. Every Surge vault includes a unilateral exit path: after a relative timelock of roughly one year, the borrower can spend the exit leaf without any cooperation from Surge or its Distributed Custody Network. The exit tooling is open-source and lives on the Surge GitHub. This is the entire point of the design. If Surge goes bankrupt, gets hacked, or is regulated out of existence tomorrow, your Bitcoin is recoverable using nothing but a Bitcoin node and the public exit software. No bankruptcy court, no creditor queue, no Celsius-style outcome.
Variable from 6.9% APR, fixed at 9.9% APR. The variable rate moves between 2% and 18% based on pool utilization. Surge has seen 80 to 95% utilization since mainnet launch, which puts most variable borrowers in the 4.5 to 8% range. There are no origination fees, no account fees, and no penalties for early repayment. You pay the interest on your outstanding balance, the on-chain Bitcoin fee to fund and unwind your vault, and Base gas fees for the EVM-side operations.
No. The Surge App runs on the Surge Protocol in the same way Aave and Morpho work: permissionless at the protocol layer with the app as one interface among many. There is no KYC at sign-up, no identity-bound account, and no jurisdiction-specific restrictions baked into the protocol. The Android app is approved by the Play Store globally; the iOS app is blocked only in China. You are still responsible for your own local tax reporting because nobody is going to file it for you.
Not directly today. Surge disburses USDC. You can spend USDC through the in-app gift card option, bridge it to your exchange of choice and sell for fiat, or hold it. Bank and card off-ramps are on the roadmap but explicitly not a priority for the team right now. For non-US users this is a real friction: getting USDC into a euro, pound, real or peso bank account adds an extra step and a fee through a centralized exchange or service like MoonPay. If you need fiat in your bank account next week, this is not the right platform for that.
50% currently. If you deposit 1 BTC at a $100,000 BTC price, you can draw up to $50,000 USDC. Surge has stated this will move to 75% once direct protocol integrations launch, but for now 50% is the ceiling. Liquidation triggers above the LTV threshold (which sits above the 50% borrow cap to give you a buffer). Liquidation is partial: any surplus BTC gets re-locked into a new vault under the same scripts. You do not lose more than you owe.
Your Bitcoin collateral stays on Bitcoin mainnet inside a Taproot vault. The credit accounting (interest, LTV monitoring, liquidation triggers, Dutch auction) runs on Base, which is Coinbase's Ethereum L2. USDC moves cross-chain via Circle's official Cross-Chain Transfer Protocol (CCTP v2). This split exists because Bitcoin script cannot easily handle interest accrual and multi-asset accounting, while EVM chains can. The tradeoff is real smart-contract risk on the Base side. The Bitcoin side is governed by a script you can read; the Base side is governed by code that requires auditing.
Surge Credit is built by Amby, Inc., founded in 2024. Co-founder Michael Borglin runs it as CEO since March 2026, after taking over from co-founder Yash Belavadi who is now CPO. Punith B M is CTO. The team builds out of Presidio Bitcoin in San Francisco. They have raised $1.8 million in pre-seed funding from investors including Autonomy, Sats Ventures, Vamient Capital, Samara AG, Double Peak Group, and Gerstenbrot Capital, plus angels Bobby Ong and TM Lee (Coingecko co-founders). The end-state governance is a two-entity model similar to Aave and Morpho: Amby Inc. builds the software, and the Surge Foundation (a non-profit legal entity, currently in formation) holds the upgrade rights.
Good fit if you hold Bitcoin you do not want to sell, you have followed the Celsius / BlockFi / Voyager bankruptcies and decided custody risk is the biggest factor in any borrowing decision, you are comfortable receiving USDC and managing the off-ramp yourself, and you can tolerate using an early-stage product. Bad fit if you need fiat in your bank account next week, you want a platform with years of liquidations behind it, you cannot tolerate Base L2 risk on the credit-engine side, or you need KYC compliance for institutional reasons. The honest summary: Surge is the most principled custody model on the market right now, and it is also the youngest.
Bitcoin.diy was contacted by the Surge Credit team in May 2026 with a request to be included on the loans comparison page. We conducted independent research, verified the technical claims against public documentation and source code, and reviewed the product on the basis of the on-chain custody model and the team's public commitments. We have not yet run the full borrow flow on mainnet ourselves. That section will be added when complete.
We have an editorial relationship with Surge that includes a planned guest piece by Surge co-founder Yash Belavadi on our Taproot vaults explainer. The Surge affiliate program launches in June 2026 and we intend to join. We are not currently enrolled and the link on this page is a plain link to surge.credit, not an affiliate URL. When that changes, we will disclose any commission income from referrals in keeping with our affiliate policy.
We were not paid to publish this review. The opinions here are ours.
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