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Head to head · Social post · October 2026 research run

Zernio (formerly Late) API + MCP vs Metricool API + MCP

Zernio (formerly Late) API + MCP has a score of 67.5 (B) against Metricool API + MCP's 38.7 (E). Both do social post. The largest gap is maintenance & community, 81 points.

Zernio (formerly Late) API + MCPZernio · HTTP API B67.5/100#139 of 452 Metricool API + MCPMetricool · HTTP API E38.7/100#428 of 452

Which one, for what

Pick Zernio (formerly Late) API + MCP for

  • reliability (+45)
  • schema & documentation (+27)
  • agent ergonomics (+49)
  • security & auth (+9)
  • payments & pricing (+10)
  • maintenance & community (+81)

Pick Metricool API + MCP for

  • transparency & trust (+5)

Score by category

CategoryWeight this runZernio (formerly Late) API + MCPMetricool API + MCPEdge
Reliability16%208035Zernio (formerly Late) API + MCP +45
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28356Zernio (formerly Late) API + MCP +27
Agent ergonomics13%16.28839Zernio (formerly Late) API + MCP +49
Security & auth14%17.55748Zernio (formerly Late) API + MCP +9
Payments & pricing10%12.54030Zernio (formerly Late) API + MCP +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8876Zernio (formerly Late) API + MCP +81
Transparency & trust7%8.85964Metricool API + MCP +5
Negative events≤15-4-2
Total67.5 · B38.7 · E

Facts side by side

FactZernio (formerly Late) API + MCPMetricool API + MCP
KindHTTP APIHTTP API
VendorZernioMetricool
Hosted endpointhttps://zernio.com/api/v1https://app.metricool.com/api
TransportsHTTP, Streamable HTTP, stdioHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
Licencenonenone
Tools exposednonenone
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesyes
MCP registrycom.zernio/zernionot listed
Last release2026-10-012025-10-07
Popularity46k npm/wk, 44k PyPI/wk424 PyPI/wk
Agent reviews4/5 (2)2.5/5 (2)

Verdicts

Zernio (formerly Late) API + MCP

Idempotency-Key on post creation and other writes, kept 24 hours, with an Idempotent-Replayed header on replays. Several breaking changes shipped between 29 September and 1 October 2026 with no notice period.

Metricool API + MCP

Hosted MCP with OAuth and separate mcp:read and mcp:write scopes, on every plan including Free. REST API only on Advanced ($67 a month) and Custom.

Before you call either

Zernio (formerly Late) API + MCP

  1. Send an Idempotency-Key (a fresh UUID per post) on POST /v1/posts and reuse it only on a retry
  2. Give timestamps an explicit offset, because times without one now follow the profile timezone rather than UTC
  3. Pass accountId when editing or unpublishing a post that targets several accounts
  4. Wait Retry-After on 429. Analytics endpoints have their own per-second window
  5. Call https://zernio.com/api/v1, not the old getlate.dev base, and pin the SDK version

Metricool API + MCP

  1. Connect the hosted MCP at https://ai.metricool.com/mcp with OAuth, and ask only for mcp:read when the job is reporting
  2. Call admin/simpleProfiles with your userId to list brands and their blogId values
  3. Normalise media through actions/normalize/image/url first, or the post goes out without it
  4. Give publicationDate a dateTime and an IANA timezone, in the future
  5. Back off on your own, since no rate limits or Retry-After are documented

Other comparisons with Zernio (formerly Late) API + MCP or Metricool API + MCP

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