Prospect Data You Can Wire Into Your Own Pipeline
Clu exposes structured search, waterfall enrichment and CRM sync through a documented REST API and an MCP server. The rate limits are published, and paid jobs run against a signed spend quote.
Clu used from Claude through the Clu MCP server. Asked: Find 25 Heads of Data or Directors of Data Engineering with Snowflake skills at Series B-C health care companies with 201-1K staff, funded since January, in the US. Two per company, none already in my lists. Enrich them and save them to Q4 Data Leaders. Claude calls search_people with nine filters, add_leads_to_list, estimate_cost and enrich_list, and reports 25 leads saved to the list Q4 Data Leaders.
10,000+ users, from founders to full sales teams
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The short answer
Clu REST API v2 lives at https://api.cleanlist.ai/api/v2 with around 30 endpoints, clapi_ Bearer auth, 14 granular OAuth scopes and a published OpenAPI 3.x spec, on Pro at $89 a seat a month and above. The Clu MCP server at https://mcp.cleanlist.ai/v1/mcp is in beta and exposes 30+ tools over OAuth, so an agent can run the same jobs your scripts run, against the same credit wallet. Paid bulk work runs behind a signed quote from POST /credits/estimate with a 5 minute TTL, and a miss costs nothing.
GTM Engineers: what gets in the way.
Tools priced for a rep in a browser break once the work runs unattended.
- 01
Limits written for a rep in a browser
The work a GTM engineer ships runs unattended: a scheduled job, a worker, an agent session. Many data tools size their limits for a person clicking through a browser, so an automated pipeline gets throttled by an export cap written for a rep doing manual research.
- 02
Evaluation costs money before it proves anything
Most vendors meter search, so the first question (does a segment this shape even exist in your data?) burns credits before a single record is enriched. A two-hour spike turns into a procurement conversation, and a lot of promising integrations never get prototyped.
- 03
Undocumented limits surface in production
Rate ceilings, daily caps and retry semantics are usually discovered at 2am when a batch job starts returning 429s with no Retry-After header. Without published numbers you cannot size concurrency, choose a backoff, or tell your on-call whether a stalled run is a bug or a limit doing its job.
- 04
Agent spend is unbounded by default
Handing a model a credit-spending API with no pre-flight quote is how a test run becomes a bill. An agent that retries a failed batch, or reads a list larger than you expected, can burn a month of credits in one session unless the server enforces the cap. A limit written into the prompt is only a request.
A Clu list called Series B sales leaders enriched through the waterfall: 6 verified work emails and 4 phone numbers found for 6 leads, 46 credits in total. Rows with no phone number found cost nothing for that field.
How Clu fits.
The mechanics a GTM engineer checks before writing the first line: endpoints, limits, cost per record, and failure behavior.
- 01
REST API v2, with the limits published up front
Base https://api.cleanlist.ai/api/v2, clapi_ Bearer auth, 14 OAuth scopes checked per endpoint, and around 30 endpoints across workspace and identity, search, lead lists, enrichment, smart agents, and sync and export. The ceilings are published: 60 requests per minute per organization, 30 per key, and a hard cap of 60 People Searches per UTC day per key. A 429 returns a Retry-After header and a rate_limited error body so a worker can back off without guessing. Access starts at Pro, $89 a seat a month.
- 02
The same jobs as MCP tools for your agent
Clu runs a remote MCP server at https://mcp.cleanlist.ai/v1/mcp with 30+ tools, connected over OAuth from Claude Settings, then Connectors, as a custom connector. There is no key to paste into a config file. It draws on the same credit wallet and the same signed-quote caps as the REST API, so an agent session and a cron job spend from one balance. It is in beta, and Clu is not in Anthropic's connector directory yet, so treat it as a working integration you install by hand.
- 03
Size a segment before you spend
POST /search/people and POST /search/companies cost nothing, and so does every read: list reads, status polls, GET /whoami, GET /credits/balance, and CSV or JSON export. Size a segment, check what the filters return, and throw the result away without touching your balance; Clu charges only when data is created. Every new Clu workspace opens on Pro for 14 days with 250 credits and 3 seats, then lands on the Free plan at 50 credits a month, which is enough to see exactly which fields come back before you commit engineering time.
- 04
Pay-for-results enrichment, through CSV or the CRM
Enrichment runs as a multi-provider waterfall, so a miss at one provider falls through to the next and the job keeps going. A verified email is 1 credit, a phone number is 10, both together are 11, a company enrichment is 1, saving a newly discovered lead to a list is 0.5, and POST /sync/crm to HubSpot or Salesforce is 0.2 per lead. Records the waterfall cannot resolve settle their reserved credits back. On our 500-lead benchmark the waterfall found 98% verified work emails and 85% phone numbers.
- Verified work emails25 leads searched23 × 123
- Phone numbersVerified before anyone calls18 × 10180
- Qualification agentFit score with reasons25 × 5125
How the alternatives compare.
Your other options are Clay, Apollo, or building the waterfall yourself on a raw data API.
| Option | Where it fits | Where it stops |
|---|---|---|
| Clay Compare | A deep workflow surface for teams happy to assemble and run the pipeline inside a vendor UI, with a large catalogue of integrations to chain | The pipeline lives in Clay tables, outside your repo, so it is harder to review, version and hand to an agent, and per-run credit use is hard to forecast before a table executes |
| Apollo Compare | An all-in-one where prospecting, sequences and an API sit behind one login, already familiar to most GTM teams | Pricing is per seat, and enrichment reads a single first-party database with no waterfall behind it |
| Build it yourself on a raw data API | Maximum control and the lowest per-record cost once volume is high and your schema has stopped moving | You become the maintainer of the waterfall: provider fallbacks, verification, retries, dedupe, credit accounting and coverage gaps all turn into code you own and get paged on |
Does Clu have an API a GTM engineer can build on?
Yes. REST API v2 sits at https://api.cleanlist.ai/api/v2 with around 30 endpoints (workspace and identity, search, lead lists, enrichment, skills, sync and export) and a published OpenAPI 3.x spec. You mint a clapi_ Bearer token from the dashboard with no approval queue and no sales call, and every endpoint checks one of 14 OAuth scopes, so a read-only key cannot start a paid enrichment. Access needs Pro at $89 a seat a month or above, or an AppSumo Tier 5+ license. Call GET /whoami first to confirm the identity, scopes, plan and organization a key resolves to.
What are the Clu API rate limits?
Clu allows 60 requests per minute per organization and 30 per API key. People Search has a separate hard cap of 60 searches per UTC day per key, which is the limit most agent workloads hit first, so plan pagination and caching around it. Going over any limit returns HTTP 429 with a Retry-After header and a rate_limited error body. AppSumo lifetime licenses without a paid plan are held to 30 requests per minute per organization.
Does the Clu API support webhooks?
No. The v2 API is poll-based. Asynchronous enrichment returns a workflow_id that you poll until the status is terminal, with exponential backoff as the recommended pattern. Synchronous operations (company enrichment, search, CRM sync, exports) answer in the same request. A scheduled job that enriches a list therefore needs a second scheduled step that polls for completion. Older tutorials that describe receiving a webhook are documenting the frozen v1 surface.
Can I call Clu from n8n, Make or Zapier?
Yes, through a generic HTTP node. There is no native Clu app in the n8n, Make or Zapier directories. Point an HTTP step at https://api.cleanlist.ai/api/v2, send your clapi_ Bearer token, and handle completion in a second scheduled step, since v2 has no webhooks. For HubSpot and Salesforce you can often skip the automation platform: POST /sync/crm pushes leads directly at 0.2 credits per lead, and POST /sync/sequencer pushes to Lemlist. Clu's own Sequences send email from your own inbox, with call tasks, inside the app, and there is no dialer. For any other tool, it hands over the record.
How do I stop an AI agent from spending more credits than I expect?
Put every paid bulk job behind a signed quote. Call POST /credits/estimate, get back an HMAC-signed quote_id with a 5 minute TTL, and pass that quote_id on the request that spends. The run cannot exceed its quote, and a stalled agent just lets the quote expire. Records the waterfall cannot resolve settle their reserved credits back. The MCP server enforces the same quote against the same wallet, so the cap holds whether the caller is your code or Claude.
Can I send a natural-language query to the Clu API?
No. The REST API takes structured filters (job title, seniority, department, headcount, industry, location and similar), and there is no natural-language search endpoint. Natural language lives one layer up, in Clu and in the MCP server, where the model turns your instruction into the same filter payload a script would send. For plain-English list requests, connect the MCP server. For a script, build the filter object against the published OpenAPI spec.
What does it cost to enrich 10,000 leads with Clu?
About 10,000 credits for verified emails, at 1 credit each. On Pro that's the 10,000-credit level at $449 a month, or on Starter or Pro a one-off 10,000-credit top-up for $449. Adding a phone number takes each record to 11 credits, or 110,000 for the file, so run the phone pass only on the accounts you will call. Records the waterfall cannot resolve settle their reserved credits back, so real spend usually lands below the worst case. Quote the job with POST /credits/estimate first and the returned quote_id caps the run.
Which filters does Clu not support?
Clu people and company search runs on firmographic and role attributes (job title, seniority, department, headcount, industry, location, funding stage and similar), 20+ filters in total. There are no intent-data, technographic or revenue-range filters, and no job-change detection or alerting. If your scoring model needs one of those signals, source it separately and join on the company domain, or filter first and let a skill (5 credits per lead) research only the records that survive.
Agents that run your GTM.
Every new Clu workspace opens on Pro for 14 days, API and MCP included, so you can see which fields come back before you write the integration.
14 days of Pro, free.
