Free Web
Free source (opens in a new tab)
Month, annual commitment
For: Checking whether an integration works
Limits
- 500 runs per month
- 5 fixes per month
Includes
- Full API catalog
- MCP server and CLI
1 more
- Bring your own agent
CodingDocumented overviewLast checked Oct 1, 2026
FetchSandbox: Pricing, Features & Best Use Cases
Verification engine for AI coding agents: runs API integration scenarios in sandboxes that simulate webhooks, retries and failures, via MCP and CLI.
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Our take: FetchSandbox fits developers who let AI coding agents write API integrations and want each fix proven on a deterministic sandbox scenario, with a free tier of 500 runs and 5 fixes per month.
Main limitation: Free is capped at 5 fixes a month, Pro costs $200 per workspace, and self-hosting plus SSO are Enterprise-only.
Who should use FetchSandbox
FetchSandbox fits developers who let AI coding agents write API integrations and want each fix proven on a deterministic sandbox scenario, with a free tier of 500 runs and 5 fixes per month. Based on the vendor's documentation, not on a hands-on test.
Best for: Developers using AI coding agents to build API integrations
Also a good fit for
- Teams needing deterministic webhook testing in CI
- Startups integrating Stripe, Twilio or auth providers
Consider another tool if free plan limited to 5 fixes per month
Or if
- Pro is $200 per workspace per month; Team $999/month
- Overages billed at $3 per fix and $5 per 10,000 runs on Pro
FetchSandbox pricing and usage limits
Prices checked Oct 1, 2026 on the official US pricing page. Official pricing ↗ Prices and limits change often.
Free access and trial conditions
Free plan, no card required
No separate trial; free tier is permanent
Paid plans: what changes as you upgrade
Pro Web
$200/mo per workspace per month source (opens in a new tab)
Month, annual commitment
For: Teams shipping agent-built integrations
Limits
- 10,000 runs and 100 fixes per month
- Overage $3 per fix and $5 per 10,000 runs
Includes
- Receipts and history
- CI gate
Team Web
$999/mo source (opens in a new tab)
Month, annual commitment
For: Larger organizations verifying many workflows
Limits
- Up to 10 workspaces
- Unlimited runs, 500 fixes; $3 per fix after
1 more
- Up to 5 of your own APIs from a spec
Includes
- Fixes as PRs from CI
Enterprise Web
Custom pricing source (opens in a new tab)
Unknown, annual commitment
For: Companies with compliance and on-prem needs
Includes
- Internal services built for you
- Drift, SSO, audit, SLA
1 more
- Self-hosted option
Usage caps, credits and extra costs
Pro overages: $3 per fix and $5 per 10,000 runs; Team $3 per fix after 500
Not stated
What is FetchSandbox, and how does it work?
FetchSandbox lets coding agents (Cursor, Claude Code, Codex, Lovable, Windsurf) test integrations against sandboxed versions of third-party APIs without real keys or charges. A run executes a full scenario — for example a Stripe payment flow with state carried between steps and the resulting webhooks — and can deliberately duplicate webhooks, deliver events out of order or fire stale events to reproduce production-style bugs. A 'fix' is a diff verified on the same scenario, failing before and passing after, with a shareable receipt URL. The MCP server and CLI are open source (MIT); the hosted engine, workflows and webhook simulation are the paid service. Pre-configured integrations include Stripe, Twilio, Resend, Clerk, Privy, AgentMail, Surge, Kulipa and WorkOS.
What you provide and what you get back
You provide
- A bug or integration task given to your agent
- Pre-configured API sandbox (Stripe, Twilio, Resend, Clerk, WorkOS)
- An OpenAPI spec on Team
You get back
- Scenario run results with webhooks
- Before/after fix verdict
- Public replayable receipt URL
Where you can use it
- Platforms
- Web
- Account
- Required
Where FetchSandbox is most useful
Scenarios are worked out by our editors from the documentation; the actual result depends on your input and plan.
Verifying agent-written API integrations before production
- Who
- Developers using Cursor or Claude Code
- You provide
- Agent-written Stripe or Twilio integration
- Expected result
- Verified run showing the integration reaches the right state
- Plan needed
- Free
- Limitation
- 500 runs per month source (opens in a new tab)
Reproducing webhook edge cases (duplicates, out-of-order, stale events) deterministically
- Who
- Backend engineers
- You provide
- An invoice.paid handler
- Expected result
- Reproduced duplicate, out-of-order or stale webhook bug
- Plan needed
- Free
- Limitation
- Counts as runs against the monthly cap source (opens in a new tab)
Gating CI on verified fixes with receipt URLs in PRs
- Who
- Engineering leads
- You provide
- Pull request with an agent fix
- Expected result
- Receipt URL pasted into the PR proving fail-before, pass-after
- Plan needed
- Pro
- Limitation
- Receipts and CI gate start on Pro source (opens in a new tab)
What FetchSandbox does, and where it stops
MCP server for Cursor, Claude Code, Codex, Lovable, Windsurf and CLI
Runs an MCP server and CLI that plug into Cursor, Claude Code, Codex, Lovable and Windsurf Lets the agent test without leaving the editor
Stateful sandboxes that fire webhooks like the real API
Simulates stateful third-party APIs that fire webhooks like the real ones Avoids real keys, charges and production data
Failure injection: duplicate, out-of-order and stale webhook events
Injects duplicate, out-of-order and stale webhook events Reproduces hard production bugs on demand
Before/after fix verification with public replayable receipt URLs
Verifies a fix as failing before and passing after and issues a replayable receipt URL Gives reviewers proof, not claims
Pros, cons and deal-breakers
Where FetchSandbox is strong
- Free tier: 500 runs and 5 fixes per month, no card required You can try it with no card and no provider signup documented source (opens in a new tab)
- No API keys or partner onboarding needed for sandboxed APIs You avoid hitting real vendor APIs during development documented source (opens in a new tab)
- Transparent USD pricing including overage rates Developers can inspect or self-run the client tooling documented source (opens in a new tab)
- MCP and CLI source code public under MIT Reviewers can verify results in a PR documented source (opens in a new tab)
Limitations to check before paying
- Free plan limited to 5 fixes per month Real project work can pass 5 fixes quickly documented source (opens in a new tab)
- Pro is $200 per workspace per month; Team $999/month Small teams face a large jump to $200 documented source (opens in a new tab)
- Overages billed at $3 per fix and $5 per 10,000 runs on Pro Teams with unusual APIs depend on Team tier documented source (opens in a new tab)
- Own-API mocking from a spec limited to 5 APIs on Team; self-hosting is Enterprise-only Self-hosting needs a sales conversation documented source (opens in a new tab)
How to use FetchSandbox for verifying an agent-written API integration
Set up FetchSandbox
- Create a free account at fetchsandbox.com
- Add the FetchSandbox MCP server to Cursor, Claude Code or another supported IDE
- Pick an API from the catalog, for example Stripe
Example: verifying an agent-written API integration
- Ask your agent to run the Stripe accept_payment scenario against the sandbox
- Enable duplicate or out-of-order webhook delivery and rerun
- Let the agent apply a fix and rerun the same scenario
- Copy the receipt URL into your pull request
Review and export the result
- Confirm the run fails before the fix and passes after
- Check remaining runs and fixes in your dashboard
Run the Stripe accept_payment scenario with duplicate webhooks against my invoice.paid handler, fix any bug you find, and give me the receipt URL.
FetchSandbox integrations and API
Native integrations and export formats
Export: Receipt URLs
API access and separate billing
FetchSandbox has no public API in its official documentation. MCP and CLI (MIT) are public; docs root returned 404
Privacy, data use and commercial rights
Summarized from the vendor's current policies; this is not legal advice and a vendor's badge is not an independent audit.
How your inputs and outputs are handled
Account email, MCP usage events and working copies of code during jobs
Policy states no model is trained on your code
Working copies deleted when the job finishes; account data kept until deletion requested; run history retained while account active
Commercial use and plan restrictions
unknown
unknown
Controls for business users
- Deletion on request
- Self-hosting on Enterprise
Policies: fetchsandbox.com/privacy
FetchSandbox alternatives by need
"Better suited" is based on documented features and pricing, not on a head-to-head test.
Cursor: better suited to
GitHub Copilot: better suited to
Devin Desktop (formerly Windsurf): better suited to
Lovable: better suited to
| Alternative | When to choose it | Pricing | Limitation | |
|---|---|---|---|---|
| Cursor | — | — | Compare | |
| GitHub Copilot | — | — | Compare | |
| Devin Desktop (formerly Windsurf) | — | — | Compare | |
| Lovable | — | — | Compare |
Explore FetchSandbox further
FetchSandbox pricing, plan by planEvery plan with USD prices, limits and what is free.Best FetchSandbox alternativesTools for the same job, by need and starting price.Best AI coding toolsOur picks in this category, compared by price and free tiers.Prompts for FetchSandboxReady-to-copy prompts with their sources.
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FetchSandbox FAQ
Is FetchSandbox free?
Yes, the Free plan gives 500 runs and 5 fixes per month for each developer with no card required. source (opens in a new tab)
What counts as a run and a fix?
A run is one complete scenario against the sandbox, such as a Stripe payment flow with webhooks; a fix is a diff proven to fail on the old code and pass on the new. source (opens in a new tab)
Do I need API keys for Stripe or Twilio?
No, sandboxed APIs need no real keys, OAuth or partner onboarding and touch no production data. source (opens in a new tab)
Is it open source?
The MCP server and CLI are MIT-licensed; the hosted engine with sandboxes and webhook simulation is paid. source (opens in a new tab)
Does it train on my code?
The privacy policy says no model is trained on your code and working copies are deleted when a job finishes. source (opens in a new tab)
Sources and review methodology
Official sources and verification dates
- FetchSandbox — A deterministic verification engine for agents homepage · checked Oct 1, 2026
- Pricing — API Sandbox Plans | FetchSandbox pricing · checked Oct 1, 2026
Not verified: API docs (docs root 404); Commercial-use terms.
How we documented and maintain this page
Every fact about FetchSandbox above comes from the 2 official pages listed here, last compared on Oct 1, 2026; we have not run FetchSandbox ourselves, so it has no editorial score. How we check and re-check pages.
Article updated Oct 10, 2026; prices checked Oct 1, 2026. Outbound links to vendors are plain links; we do not earn commissions. How we review · Report an error