> ## Content Index > Fetch the complete content index at: https://stablecoininsider.org/llms.txt > Use this file to discover other available public pages before exploring further. # Best Transaction Security APIs for Wallets and Payment Apps - URL: https://stablecoininsider.org/best-transaction-security-apis-wallets/ - Published: 2026-11-13T11:12:42.000Z - Updated: 2026-11-13T11:12:42.000Z - Description: Six transaction security APIs compared for wallets and stablecoin payment apps, on whether they simulate before signing or only check blocklists. - Author: Milos Djukanovic - Tags: Analysis, Stablecoins, Security On 21 February 2025, Bybit's signers approved what looked like a routine transfer and lost about 1.5 billion dollars. Malicious JavaScript planted in Safe's web interface had changed the transaction while they signed it. The code only switched on for Bybit's contract and one other address, and was swapped back for clean files two minutes after the theft. Nothing on the signers' screens showed what they were really approving. So this compares six transaction security APIs on the question that attack raises: does the tool show what a transaction will actually do before anyone signs, or does it only check addresses against a list? > A blocklist only knows attacks that have already happened. Simulating the exact transaction before signing is what catches the new one, as long as the check runs outside the interface the attacker controls. ### Key Takeaways - Simulation shows what a transaction does before anyone signs it. - Blockaid and Hypernative lead on pre-signing simulation for large wallets. - GoPlus is the only full suite with published monthly prices. - Scam Sniffer sells reputation data, from 999 dollars a month. - Two tools in this category have shut down or lost their domain. --- ## What Actually Differs Every API here returns a risk verdict. They differ in what they look at to reach it. Simulation runs the transaction against current chain state and reports the balance changes, approvals and calls it would make. Reputation checks look up the destination address, token, dApp or URL against known bad actors. Both matter, because most retail losses still come from known scam patterns, as our guide to [**stablecoin scams**](https://stablecoininsider.org/stablecoin-scams/) shows. Targeted attacks on businesses, though, use addresses no list has seen yet. **What to note:** ask each vendor whether its verdict comes from simulation, reputation or both, and what happens when they disagree. --- ## Best Transaction Security APIs for Wallets and Payment Apps ### 1\. [Blockaid](https://blockaid.io/wallet-providers) [![Blockaid](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-blockaid.jpg)](https://blockaid.io/wallet-providers) **Does the job:** pre-signing transaction scanning used by the largest consumer wallets. Blockaid's wallet page carries testimonials from Coinbase Wallet, MetaMask, Zerion, Rainbow, Backpack and Core. The platform supports: - Transaction scanning that shows state changes before signing - Address scanning, including links to OFAC-sanctioned entities - Token scanning for drainers, rug pulls and spam - dApp scanning when users connect - Human-readable explanations and verdicts in under 300 ms Blockaid claims 99.998 percent accuracy and false positives under 0.002 percent, without published methodology. Its platform page cites 50+ chains while its wallet page lists Ethereum plus six or more EVM chains, and no pricing is published. Best for consumer wallets and embedded wallet providers at scale. ### 2\. [Hypernative Wallet Protection](https://www.hypernative.io/product/wallet-protection) [![Hypernative Wallet Protection](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-hypernative.jpg)](https://www.hypernative.io/product/wallet-protection) **Does the job:** simulation and threat detection in one API call, from an onchain monitoring vendor. Hypernative's wallet product returns a simulation, a risk score and an approve or deny recommendation from a single endpoint. The platform supports: - Pre-transaction simulation with readable balance changes and approval grants - Detection of phishing, drainers, address poisoning and pig-butchering infrastructure - Token screening for honeypots, impersonation and malicious airdrops - Monitoring of incoming transactions after the fact - A claimed 300+ threat vectors across 75+ chains The page claims 96 percent scam detection in benchmarking and "4X" effectiveness against legacy providers, with no baseline given. Reown is the only named customer, and pricing is by demo only. Best for wallets that want simulation and ongoing monitoring from one vendor. ### 3\. [GoPlus Security](https://gopluslabs.io/security-api) [![GoPlus Security](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-goplus.jpg)](https://gopluslabs.io/security-api) **Does the job:** the broadest self-serve security API, with prices on the page. GoPlus says its APIs handle 10 million calls a day, and it is the only vendor here with a full public price list. The platform supports: - Token, NFT and approval security checks - Malicious address and phishing site detection - A Transaction Simulation API and signature decoding - dApp security information and rug-pull detection in beta - A free tier, then plans from 199 to 3,499 dollars a month The pricing page contradicts itself on batch calls, with the table enabling them from the 199 dollar plan and the Q&A limiting them to Pro and above. No customers are named on the API page. Best for startups that need to test several checks before talking to sales. ### 4\. [Chainalysis Hexagate GateSigner](https://www.chainalysis.com/product/hexagate/) [![Chainalysis Hexagate GateSigner](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-hexagate.jpg)](https://www.chainalysis.com/product/hexagate/) **Does the job:** a co-signer that simulates every transaction and refuses to sign the bad ones. GateSigner is part of Chainalysis's Hexagate product, and it works as an extra signer or API rather than a warning inside your interface. The platform supports: - Simulation of each transaction before signing - Deployment as a co-signer or through an API - Compatibility with Safe multisig setups - Automatic denial of hidden approvals or role grants - Hexagate's wider monitoring across 75+ chains GateSigner is built for treasuries and protocols, not for scanning millions of retail wallet transactions. Chainalysis publishes no pricing, and its own security incident in late October 2026 took several products offline for about a week. Best for business treasuries and multisigs that want a check the front end cannot override. ### 5\. [Webacy](https://docs.webacy.com/api-reference/introduction) [![Webacy](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-webacy.jpg)](https://docs.webacy.com/api-reference/introduction) **Does the job:** a risk score API that now scans and simulates transactions before execution. Webacy's documentation describes a single Risk Score API for addresses, transactions, contracts, tokens and URLs, with a transaction scanning module it calls KYT. The platform supports: - Transaction scanning that scans and simulates transactions for risk - Threat risk checks and OFAC sanctions screening for addresses - Real-time smart contract and token analysis - Stablecoin endpoints, including a depeg monitor and stablecoin risk grades - More than a dozen chains, including Ethereum, Solana and Hedera The docs tell integrators to treat missing, stale or errored data as unknown and to fail closed, which is sound advice for any vendor here. Its older API overview page now returns a 404, rate limits depend on plan, and alerts help in [**the first hour**](https://stablecoininsider.org/stablecoin-theft-first-hour/) after a theft but cannot replace a pre-signing block. Best for apps that want transaction, sanctions and token checks from one risk API. ### 6\. [Scam Sniffer](https://scamsniffer.io/) [![Scam Sniffer](https://storage.ghost.io/c/73/6a/736af0e4-2274-4543-a329-2952b2b52abc/content/images/2026/11/txsec-scamsniffer.jpg)](https://scamsniffer.io/) **Does the job:** scam domain and address intelligence, sold as an API and a data feed. Scam Sniffer tracks over 420,000 malicious domains and 61,000 malicious addresses, and publishes much of its domain list for free. The platform supports: - Domain, URL and address checks with BLOCKED or PASSED verdicts - Address labels, categories and source transactions on Enterprise - A free open-source domain blacklist, updated daily - Block-by-block monitoring of Ethereum for drains and poisoning - A Standard plan from 999 dollars a month Scam Sniffer does not simulate transactions, so it cannot catch a malicious call to an address it has never seen. Logos for Binance, Phantom, Rabby and others appear on the page without the relationship described. Best for exchanges and wallets adding a reputation layer alongside simulation. --- ## Transaction Security APIs Compared | API | Simulates before signing | Reputation checks | Pricing | Named users | | ------------------- | ------------------------- | ----------------------------------- | ----------------------------- | --------------------------------- | | Blockaid | Yes | Address, token, dApp | Not published | Coinbase Wallet, MetaMask, Zerion | | Hypernative | Yes | Phishing, token, dApp | Not published | Reown | | GoPlus | Yes, simulation API | Token, address, approval, phishing | Free to 3,499 dollars a month | None on page | | Hexagate GateSigner | Yes, as a co-signer | Chainalysis attribution data | Not published | None on page | | Webacy | Yes, transaction scanning | Address, sanctions, contract, token | Plan-based, not on page | None on page | | Scam Sniffer | No | Domain, address | From 999 dollars a month | Logos only | Five of the six APIs can now show what a transaction will do. Scam Sniffer is the exception, and it can only tell you whether a counterparty has a bad record. **What to note:** test each API with a transaction to a brand-new contract, since that is what a targeted attack looks like. --- ## Where the Check Runs The Bybit attack did not exploit Safe's contracts. It changed the transaction inside the browser, the same place where a wallet would normally display its security warning. That is the weak point of any client-side check. If the code that builds the transaction is compromised, the code that explains it can be compromised too. The defensive pattern is to simulate on an independent service and compare the result with what the signing device itself displays. For business treasuries, that means pairing an API with a co-signer or policy engine rather than trusting one screen. **What to note:** ask whether the vendor can run as a separate approval step, not only as a warning inside your own interface. --- ## How to Choose ### 1\. Decide what you are protecting Retail users mostly lose money to known scams, so reputation data catches a lot. Business treasuries face targeted attacks, so simulation matters more. ### 2\. Require pre-signing simulation for large transfers For anything above a set threshold, the user or signer should see balance changes before approving. Blockaid, Hypernative, GoPlus, Webacy and Hexagate GateSigner offer this. ### 3\. Put the check outside your own front end Run simulation through a service or co-signer your web interface cannot alter. Tie it into your [**key management setup**](https://stablecoininsider.org/best-key-management-mpc-providers/) so policy, not a pop-up, blocks risky transactions. ### 4\. Add a reputation layer cheaply Scam Sniffer's free domain list and GoPlus's free tier cost little to add. They catch the bulk of phishing before simulation is even needed. ### 5\. Measure false positives on your own traffic A tool that blocks too many legitimate payments will be switched off. Run it in warning mode for a few weeks before enforcing. **What to note:** confirm latency under load, because a slow check at checkout costs conversions. --- ## How This List Was Built Inclusion required three things, so that the comparison means something. - A first-party page or documentation describing an API that wallets or apps can integrate - Checks that run on transactions, addresses or URLs in real time - A product available to new customers today Wallet Guard was left out because it shut down on 31 March 2025, and Harpie because its former domain no longer hosts the product. Wallet extensions that do not sell an API were also excluded. Providers who believe they meet the three criteria above are welcome to send documentation for consideration in the next update. **What to note:** last reviewed against vendor websites in November 2026. --- ## Risks and Limitations - Accuracy and detection figures are vendor claims without published test methods. - A check that runs inside a compromised interface can be bypassed or faked. - Reputation lists miss attacks that use new addresses or domains. - False positives can block legitimate payments and frustrate users. - Most vendors do not publish prices, so costs are unknown until a quote. --- ## Conclusion The Bybit theft showed that a signer can approve a transaction that looks normal and is not. The best transaction security API is the one that shows the real effect of a transaction before it is signed. Blockaid and Hypernative lead on simulation for large wallets, GoPlus offers the most open pricing, Hexagate GateSigner suits treasuries that want a co-signer, Webacy combines transaction, sanctions and token checks, and Scam Sniffer adds reputation data cheaply. Most teams need both layers. Use reputation data to catch the common scams, and simulation, run outside your own interface, to catch the targeted one. ***Read Next:*** - [**Stablecoin Scams and How to Spot Them**](https://stablecoininsider.org/stablecoin-scams/) - [**What to Do in the First Hour After a Theft**](https://stablecoininsider.org/stablecoin-theft-first-hour/) - [**Best Key Management and MPC Providers**](https://stablecoininsider.org/best-key-management-mpc-providers/) --- ## FAQs: ### 1\. What is transaction simulation in crypto? It runs a transaction against current chain state without broadcasting it, then shows the balance changes, approvals and contract calls it would cause. ### 2\. Would transaction simulation have stopped the Bybit hack? Only if it ran outside the compromised Safe interface and signers compared its result with what they were approving. A check inside the same interface could have been altered too. ### 3\. What is the difference between simulation and a blocklist? A blocklist checks whether an address or domain is already known to be malicious. Simulation shows what the transaction itself will do, even if every address involved is new. ### 4\. Which transaction security API publishes its prices? GoPlus publishes plans from free to 3,499 dollars a month, and Scam Sniffer's Standard plan starts at 999 dollars a month. The others quote on request. ### 5\. Do stablecoin payment apps need transaction security APIs? Yes, if users sign transactions from the app. Stablecoin transfers are hard to reverse, so blocking a bad transaction before signing is far cheaper than recovering funds afterwards. --- ***Disclaimer:*** This content is provided for informational and educational purposes only and does not constitute financial, investment, legal, or security advice; no material herein should be interpreted as a recommendation, endorsement, or solicitation, and readers should conduct their own independent research or consult a qualified professional. Features, accuracy claims, customer names and prices are drawn from each vendor's own website or news reports at the time of writing, are not independently verified here, and change frequently. No security API guarantees that a malicious transaction will be detected. Confirm current features, terms and pricing directly with each vendor before integrating one.