ZeroBounce vs ZoomInfo API + MCP

ZeroBounce 54

No OpenAPI or other machine-readable contract found; a Postman collection is linked (5 of 25). llms.txt lists marketing pages, and the docs have no Markdown twins (5 of 10). Endpoint pages explain timing, credits and when to use batch or file APIs (14 of 20). Parameter tables and listed status and sub-status values, including the ai_agent_mailbox sub-status added in July 2026 (10 of 15). Examples per endpoint, a sandbox and an error-code page (12 of 15). v2 paths, an API migration page and dated maintenance notices on the status page, with no API changelog (8 of 15). 5+5+14+10+12+8 = 54.

ZoomInfo API + MCP 84

Eight public OpenAPI 3.0 files, with 18 operations in the Data API file (25). llms.txt and Markdown twins on docs.gtm.ai and gtm.ai (10). Endpoint descriptions state when to search before enriching and how to find valid field names, and MCP tool pages mark superseded tools (16 of 20). The Data API file marks required fields 198 times but has 11 enums, because filter values come from Lookup calls (10 of 15). 150 examples in the Data API file and an error catalogue with codes and a recommended action each (13 of 15). The API is versioned as v1 with breaking changes promised only in a new version. The dated Release Hub covers the whole product with an API filter, newest entries 20 October 2026, and docs.gtm.ai has no changelog of its own (10 of 15). The credit page says rate-limit headers are not returned while the rate-limit page lists them.

ZeroBounce 70

Closed service. The JavaScript SDK 3.0.0 was published on 25 October 2026 (30). No API changelog; the dated changes found in 90 days are that release and status-page notices, fewer than three releases (10 of 20). Support by email and 24/7 chat per the docs, a public status page; replies not tested (10 of 15). Official SDKs in many languages and an MCP server (15). Package health not checked (5 of 10). 30+10+10+15+5 = 70.

ZoomInfo API + MCP 83

GTM CLI v2.2.1 on 28 October 2026 (30). CLI releases 1.1.0, 2.0.0, 2.1.0, 2.1.1, 2.2.0 and 2.2.1 since 26 August, plus Release Hub entries dated 1, 5, 6, 9, 13, 19 and 20 October 2026 (20). A public Release Hub, a support address in the docs and a GitHub issue tracker for the CLI, whose handling we could not see (10 of 15). The hosted server is in the official MCP registry as io.github.Zoominfo/zoominfo-mcp at 1.0.1, published 3 September 2026, pointing at https://mcp.zoominfo.com/mcp, under the GitHub namespace of the vendor's own organisation. The 9 October check could not reach the registry. No official SDKs, and the CLI is current (15). The CLI repository has release workflows, semantic-release and npm provenance attestations (8 of 10). 30+20+10+15+8 = 83.

ZeroBounce 63

Closed service under terms naming Hertza L.L.C. (ZeroBounce) of Nevada; SDKs and MCP server open source (15 of 30). The data protection page says uploaded data is never kept more than 30 days, the privacy policy of 30 June 2026 keeps account data 'as long as needed', and EU and UK DPAs are published (22 of 30). An API migration page, with no dated deprecation policy (6 of 20). A sub-processor list naming each provider and the data exchanged (16 of 20). 15+22+6+16 = 59.

ZoomInfo API + MCP 76

Closed service with published terms naming ZoomInfo Technologies LLC, and an MIT CLI (15 of 30). The privacy policy covers people in the database and customers, names sources (web scanning, third parties, a research team, customer contributions and ZoomInfo Lite email access), a Data Protection Officer contact and a removal route. Retention has no fixed period, and the pricing page says both that credits never expire and that they expire after 12 months (22 of 30). Two rate-limit headers carry a removal date of 1 January 2027 and breaking changes are promised only in a new API version, but superseded MCP tools carry no dates and no deprecation policy was found (10 of 20). Sub-processor list updated 17 July 2026 with locations and roles (18 of 20).

ZeroBounce 75

Hosted lines. Statuspage at status.zerobounce.net with API, API-US, API-EU, Bulk API, website and Cloudflare components (20). The incident feed for 8 August to 6 November shows a 6-minute members platform disruption on 9 September, about 3 minutes of reduced EU API availability on 1 October, and a file upload issue on 26 October resolved within 6 minutes, all minor (20). Limits published per endpoint group with numbers and block lengths (15). 429 is documented with advice to throttle, but no Retry-After, and a block can last an hour or a day (10 of 15). No SLA found (0). Generally available (10). 20+20+15+10+0+10 = 75.

ZoomInfo API + MCP 87

Graded with the hosted lines. Atlassian Statuspage at status.zoominfo.com with 16 components, among them ZoomInfo Enterprise API, Enrich and GTM Studio (20). The history page for 3 August to 1 November 2026 shows one major incident on GTM Studio audiences on 4 September lasting 93 minutes, an eight-hour audiences issue on 24 September marked no impact, a list-processing issue on 4 August, a NeverBounce job-processing incident on 28 October marked minor, Chorus incidents, and none naming the API component (20 of 30). Limits published per package on three windows, from 5 a second on Builder to 35 on Scaling (15). 429 carries Retry-After and names the exhausted window, and rejected requests do not consume quota. No idempotency keys found for audience writes (12 of 15). The Licence Terms and Conditions guarantee 99.9 per cent monthly availability (10). API v1, MCP server and CLI carry no beta label (10).

ZeroBounce 35

No x402, MPP or L402 (0). Per-credit prices public, from $39 for 2,000 validations (20). Freemium of 100 validations a month for business or premium domains; a card requirement isn't stated, and free webmail addresses don't qualify (15 of 20). A person signs up in a browser (0). 0+20+15+0 = 35.

ZoomInfo API + MCP 40

No x402, MPP or L402 (0). Per-credit prices are public, $0.05 an AI credit and $0.38 a data credit at the $1,000 spend tier, with top-ups from $20 (20). A free account with 1,000 data credits and 1,000 AI credits needs no card (20). A person signs up and completes OAuth in a browser (0).