Tenderly Alternatives for Debugging and Simulating Transactions

Tenderly is still running, but its pricing has changed shape. The pricing page now lists Tenderly Free, described as "Free, indefinitely", with a full debugger, a single-chain explorer, single-transaction simulation and browser access. It says plainly that there is "No API access on Free." Everything else sits in Tenderly Console, a custom contract with "No tiers" that is sized through a sales call. The old Starter and Pro plans appear only as legacy plans in the FAQ.

That split pushes two groups to look elsewhere: solo developers who want simulation from code without a sales conversation, and teams that want a public price. Two other tools people used next to Tenderly have also gone. OpenZeppelin retired the hosted Defender service on July 1, 2026, and Alchemy turned off its alchemy_simulate* methods on September 30, 2026.

No single product below copies all of Tenderly. The list is split by job: tracing and debugging a transaction, running a shared fork, and watching contracts in production. If you are also replacing an old Truffle and Ganache setup, our Truffle alternatives guide covers the local frameworks in more depth.

Prices below are as of November 6, 2026. Our method is on How we review tools.

Quick comparison

Foundry

Most of what developers open Tenderly for, looking at why a transaction reverted, Foundry can do from a terminal. cast run takes the hash of a published transaction, re-executes it locally against an RPC and prints the trace. Add --debug to open it in the interactive debugger, or --trace-printer for opcode-level output.

The same toolchain covers simulation before you send. anvil --fork-url starts a local copy of any EVM chain at a chosen block, and forge runs Solidity tests and scripts against it. Everything is free and on GitHub, with v1.8.6 as the latest stable release from October 21, 2026.

Best for: Developers who want to trace, debug and simulate from the command line at no cost.

Pricing:

• Free and open source
• You pay only for the RPC endpoint you fork from

Watch out for:

• Traces live in your terminal, so there is no shareable link like a Tenderly transaction page. Teammates have to rerun the command.
• The --quick flag uses only the previous block's state, and the reference page warns it may give different results than the live execution.

Official site: Foundry.

Phalcon Explorer

Security teams know BlockSec's Phalcon Explorer from post-mortems of exploits. Paste a transaction hash and the docs list what you get: the call sequence, source code, asset balance changes, money flow, gas profiling and state changes. It also offers a debugger and a simulator.

Coverage is wide. The explorer lists 19 mainnets, among them Ethereum, Solana, Base, Arbitrum, Linea, Monad and HyperEVM, plus Sepolia and Hoodi testnets. The simulator places a transaction at any position in any block, which is handy for asking what would have happened one slot earlier.

Best for: Reading an unfamiliar or malicious transaction in a browser, with balance changes and fund flow laid out.

Pricing:

• No public price in the Phalcon docs
• Phalcon Security, the monitoring and blocking product, has its own sales process

Watch out for:

• The simulator supports only six chains (Ethereum, BSC, Arbitrum, Optimism, Avalanche and Polygon), far fewer than the explorer.
• Shared simulation links expire after 48 hours, per the simulator docs, so save results you need later.

Official site: Phalcon Explorer.

BuildBear

BuildBear sells the piece of Tenderly that teams share: a hosted fork, called a sandbox, that has its own RPC URL. Front-end developers, QA and auditors can point a wallet at the same forked chain without each running a local node, which is how many teams used Tenderly Virtual TestNets.

Plans are priced in public. The pricing page lists the number of sandboxes, throughput in RU/s, and a monthly call allowance per tier. Static RPC URLs and REST API access start on the Developer plan, and beta plugins come with Team.

Best for: Teams that need a persistent shared fork for staging, demos or QA, with a price they can see.

Pricing:

• Explorer: free, 2 sandboxes, each limited to 3 days, 1,000 RU/s
• Developer: $49/month, 5 persistent sandboxes, 2,000 RU/s
• Team: $199/month, 30 persistent sandboxes, 5,000 RU/s
• Enterprise: from $499/month, unlimited sandboxes

Watch out for:

• The free plan only gives basic sandbox access with limited historical block access, so long-running staging needs a paid plan.

Official site: BuildBear.

Sentio

Sentio started as an indexing and monitoring platform and added a transaction debugger. The debugger docs describe a trace view where you can jump to any point in execution, a call stack panel, and two modes: function-only by default, and single-step for going line by line.

The rest of the product is closer to Tenderly's monitoring side: processors that index your contracts, dashboards, alerts and an RPC node. Billing is by Sentio Units (SU), which makes the free tier usable for a single project and charges by volume after that.

Best for: Protocol teams that want debugging, dashboards and alerts in one account with usage-based billing.

Pricing:

• Free: 200 million SU, 5 projects, 1 alert, 2 collaborators per project, 2,000 RPC requests per minute
• Pay As You Go: $0.03 per 1M SU for the first 3B, $0.02 per 1M after; 20 projects, 20 alerts
• Enterprise: custom, 99%+ uptime SLA

Watch out for:

• The free plan allows one alert in total, so any real monitoring setup moves to Pay As You Go fast.

Official site: Sentio.

Hardhat

Hardhat fits teams whose simulation happens inside a test suite rather than a dashboard. Hardhat 3 runs TypeScript tests with viem and Solidity tests side by side, and its docs include pages on multichain and OP Stack support, so L2 behaviour can be checked in the same repo.

The simulated network ships as EDR, a separate npm package at 0.25.0, while Hardhat itself is at 3.21.2 from October 29, 2026. Nothing leaves your machine or CI runner, which matters for unreleased contracts.

Best for: TypeScript teams that want simulation and debugging as part of CI, not a hosted UI.

Pricing:

• Free and open source under the MIT licence

Watch out for:

• Hardhat 3 needs Node.js v22.13.0 or later, per the getting started page, and offers no hosted transaction pages to share.

Official site: Hardhat.

OpenZeppelin Monitor

Teams that ran Defender Sentinels, or Tenderly alerts, can self-host OpenZeppelin Monitor instead. Per the docs, it watches events, function calls and transactions in real time and sends alerts to Slack, Discord, email, Telegram, webhooks, or custom Python, JavaScript or Bash scripts.

It covers EVM networks, Stellar and Solana, with partial support for Midnight. The service is written in Rust and runs as a binary or through Docker Compose. A sibling project, OpenZeppelin Relayer, handles transaction sending, and OpenZeppelin offers a managed service through a request form.

Best for: Security-minded teams that want contract alerts on their own infrastructure after the Defender shutdown.

Pricing:

• Free and open source under AGPL v3
• Managed hosting: no public price, request form only

Watch out for:

• You run and patch it yourself. Building from source needs Rust 1.90 or later, and production use should stick to the stable v1.3.x line, not the main branch.
• The AGPL v3 licence can be a blocker for companies with strict open source policies.

Official site: OpenZeppelin Monitor.

Alchemy

Alchemy is an RPC provider, and it fits here only for teams that want simulation as an API call instead of a UI. Since its own simulation methods ended, the path is standard JSON-RPC: eth_call for a quick will-it-revert check, eth_simulateV1 for simulated execution, and debug_traceCall with a callTracer when you need the full trace.

For asset changes, Alchemy suggests alchemy_getAssetTransfers scoped to the block. The free tier is large enough for development work, and paid usage is billed per compute unit with no monthly minimum.

Best for: Backend developers who already use Alchemy RPC and want to simulate transactions from code.

Pricing:

• Free: 30M compute units per month, 300 CU/s, 5 apps
• Pay as You Go: $0.52 per 1M CUs, 10,000 CU/s included; extra capacity $160 per 5,000 CU/s block per month
• Enterprise: custom

Watch out for:

• The whole Transaction Simulation API family stopped working on September 30, 2026. Code that called alchemy_simulateExecution or alchemy_simulateAssetChanges must be rewritten.
• Alchemy's note says eth_simulateV1 does not expose full execution traces, so you get far less detail than a Tenderly simulation without extra calls.

Official site: Alchemy.

How to choose

When to stay with Tenderly

Stay on Tenderly Free if you only debug and simulate by hand in a browser: the pricing page keeps the full debugger and single-transaction simulation free with no trial clock. Teams on a legacy Starter or Pro plan that use hosted virtual environments, monitoring and the API together should get a Console quote before they replace three parts at once.

Frequently asked questions