UserCheck
Identity & SecurityDetect disposable and temporary email addresses with the UserCheck API, checking an email or a domain. Agents block throwaway signups before they consume a trial or a credit.
What This Integration Enables
The easy version of this problem is already solved. An address at a ten minute mailbox provider is a throwaway, and any list catches it. The version that costs money is the near miss, and UserCheck is built around admitting that near misses exist. Check Email returns the normalized address with sub addressing and provider aliases stripped, then reports disposable, public_domain, relay_domain, free_subdomain, role_account, spam and blocklisted as separate boolean flags rather than a single verdict. Alongside them come deliverability signals including MX records and detected mailbox providers, SPF and DMARC posture, domain age, and a did_you_mean suggestion when the address looks like a typo of a real domain. Check Domain answers the same question for a domain with no address attached, which is what you want when vetting a company or cleaning a list in bulk.
Those flags mean different things and deserve different treatment. A relay domain is a privacy forwarding service used by people with real credit cards. A role account is a shared team inbox, which is a poor fit for a personal trial and a perfectly normal address for a procurement contact. Treating them all as disposable is the mistake this connector exists to help you avoid. A custom blocklist adds domains UserCheck does not classify as disposable but you still want rejected, and Evaluate Gate Decision moves the accept, block or challenge policy itself into UserCheck and returns the matched rule that produced the verdict. FlowRunner agents run all of that at the moment of signup, act on the unambiguous ends, and route the middle to a person. Blocklist operations and several enrichment fields require a UserCheck Pro plan.
Without FlowRunner
With FlowRunner
Use Case Scenarios
Trial abuse screening that does not punish privacy
A free trial signup arrives. The agent calls Check Email. If disposable is true, the signup is rejected with a message inviting the user to try a permanent address. If every flag is clear, the account provisions immediately and the record lands in HubSpot. If relay_domain or free_subdomain is true, the agent does neither: it holds provisioning and posts the case to the growth channel in Slack with the domain age, the MX provider and whether the same relay domain has appeared before. Trial abuse gets stopped. Privacy conscious buyers do not get treated as abusers.
Typo recovery at the point of capture
A lead submits an address with a domain one character off a real one. Rather than accepting an address that will hard bounce, the agent reads the did_you_mean suggestion from Check Email and, before any nurture sequence begins, offers the corrected address back to the submitter for confirmation. Addresses that are confirmed continue into the campaign in Mailchimp with the corrected value. Nothing is silently rewritten on the person's behalf.
Domain vetting during list hygiene and checkout
Before a bulk import, the agent runs Check Domain across the distinct domains in the file, which is far cheaper than checking every address, and reports which have no MX records, which are disposable, and which are free subdomain providers. At checkout in Stripe, the same agent calls Evaluate Gate Decision so the accept, block and challenge policy lives in the UserCheck dashboard where a non engineer maintains it, and the workflow simply honours the returned action and records the matched rule with the order.
Human-in-Loop Highlight
Getting disposable email detection wrong in the strict direction locks out paying customers, and it does so invisibly. The person rejected at signup does not file a ticket. They leave, and nobody in the company ever learns that the block fired on a real buyer. That asymmetry is exactly what a digital andon cord is for: the agent stops when the cost of proceeding is a mistake nobody will report.
So the agent grades rather than judges. A true disposable flag is a rejection it handles alone. A completely clean result is a provision it handles alone. The middle band stops: relay_domain true, meaning an Apple or Firefox style forwarding alias that real customers use to protect their inbox; role_account true, meaning a shared team address that is wrong for a personal trial and right for a procurement contact; or a did_you_mean suggestion on an otherwise valid domain. The agent posts the case with the evidence and the specific flag: "signup from a relay domain, MX resolves to a major provider, domain age 4,100 days, no disposable or spam flags. Provision, challenge, or reject?" One person answers in seconds and the account either opens or does not.
The blocklist gets the same treatment, for a structural reason worth naming. Add Domains To Blocklist In Bulk accepts up to 1,000 domains in a single call, and Remove Domain From Blocklist removes exactly one. Adding is a thousand times faster than undoing, and every domain added makes Check Email and Check Domain report blocklisted for every future address at that domain, permanently, until somebody removes it by hand. An agent that sees a burst of abuse from a domain therefore proposes the addition, names the domain and the evidence, and waits for a person to approve it. The blocklist is a policy, and policies get owners.
Agent Capabilities
9 actionsValidation
2- Check Email Checks a single email address against UserCheck's disposable email intelligence. Returns the normalized address with sub addressing and provider aliases stripped, the domain, and separate risk flags for disposable, public_domain, relay_domain, free_subdomain, role_account, spam and blocklisted, plus deliverability signals including MX records and mailbox providers, SPF and DMARC posture, domain age and a did_you_mean typo suggestion. Used at signup, checkout and lead capture before an account is created.
- Check Domain Checks whether a domain is used for disposable or temporary email addresses without needing a full address. Returns the normalized domain with the same flag set, MX records and detected mailbox providers, SPF and DMARC posture, domain age in days and a did_you_mean suggestion. The efficient choice for vetting a company domain, an allowlist entry, or cleaning a list by domain.
Gates
1- Evaluate Gate Decision Submits an email address, a domain and an IP address to a Gate configured in the UserCheck dashboard and returns the rule based verdict. The decision carries an action of allow, block or challenge plus the matched rule that produced it, alongside the enriched signals used to reach it. Use this instead of Check Email when the accept and reject policy should live in UserCheck rather than in the workflow.
Blocklist
5- List Blocklisted Domains Returns the custom blocklist for the environment tied to the API key as a paginated list of domains with the timestamp each was added, including the pagination metadata a workflow needs to iterate every page.
- Add Domain To Blocklist Adds a single domain to the custom blocklist for the environment tied to the API key. Once added, Check Email and Check Domain report blocklisted as true for that domain. Adding a domain that is already blocklisted fails validation.
- Add Domains To Blocklist In Bulk Adds up to 1,000 domains to the custom blocklist in one call. The operation reports partial success with succeeded and failed counts, the stored domains, and an errors array naming each rejected domain and why. Used to seed a blocklist from an existing list or sync from another system.
- Get Blocklisted Domain Looks up a single domain in the custom blocklist and returns it with the timestamp it was added. The request fails with a not found error when the domain is not blocklisted, which makes it a direct membership test before adding or removing an entry.
- Remove Domain From Blocklist Removes a domain from the custom blocklist so Check Email and Check Domain stop reporting it as blocklisted. Removes one domain per call, and fails with a not found error when the domain is not currently blocklisted.
Account
1- Get Account Status Retrieves the authenticated account's plan and current quota consumption, returning plan name, included credits and per second rate limit, the account owner, and usage counters with the timestamp at which the quota resets. Used to monitor credit burn or halt a workflow before the quota is exhausted.
Frequently Asked Questions
What can FlowRunner do with UserCheck?
FlowRunner agents can run Check Email, Check Domain, and Get Account Status in UserCheck, plus 6 more actions.
Does connecting UserCheck to FlowRunner require OAuth?
No. UserCheck connects to FlowRunner with an API key, no OAuth flow required.
Can UserCheck trigger a FlowRunner workflow automatically?
UserCheck doesn't currently expose triggers in FlowRunner. It connects as an action step inside workflows started by another trigger.
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