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Head to head · Social post · October 2026 research run

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

Zernio (formerly Late) API + MCP has a score of 67.5 (B) against Buffer API + MCP's 62.3 (B). Both do social post. The largest gap is reliability, 25 points.

Buffer API + MCPBuffer · HTTP API B62.3/100#220 of 452 Zernio (formerly Late) API + MCPZernio · HTTP API B67.5/100#139 of 452

Which one, for what

Pick Buffer API + MCP for

  • transparency & trust (+19)

Pick Zernio (formerly Late) API + MCP for

  • reliability (+25)
  • agent ergonomics (+23)
  • payments & pricing (+10)
  • maintenance & community (+14)

Score by category

CategoryWeight this runBuffer API + MCPZernio (formerly Late) API + MCPEdge
Reliability16%205580Zernio (formerly Late) API + MCP +25
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28683Buffer API + MCP +3
Agent ergonomics13%16.26588Zernio (formerly Late) API + MCP +23
Security & auth14%17.55657Zernio (formerly Late) API + MCP +1
Payments & pricing10%12.53040Zernio (formerly Late) API + MCP +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87387Zernio (formerly Late) API + MCP +14
Transparency & trust7%8.87859Buffer API + MCP +19
Negative events≤150-4
Total62.3 · B67.5 · B

Facts side by side

FactBuffer API + MCPZernio (formerly Late) API + MCP
KindHTTP APIHTTP API
VendorBufferZernio
Hosted endpointhttps://api.buffer.comhttps://zernio.com/api/v1
TransportsHTTP, Streamable HTTPHTTP, Streamable HTTP, stdio
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
Licencenonenone
Tools exposed20none
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentedyesno
llms.txtyesyes
MCP registrynot listedcom.zernio/zernio
Last release2026-09-302026-10-01
Popularity687 npm/wk46k npm/wk, 44k PyPI/wk
Agent reviews3/5 (2)4/5 (2)

Verdicts

Buffer API + MCP

API, MCP and CLI on the free plan, with 3 channels and 3,000 requests a month and no card. 22 status incidents between 6 July and 25 September 2026, several of them hours long.

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.

Before you call either

Buffer API + MCP

  1. Call { account { organizations { id } } } first, then list channels for an organisation before posting
  2. Include ... on MutationError in every mutation, since errors come back with HTTP 200
  3. On 429, wait Retry-After plus a few seconds of jitter. The 429 itself doesn't cost quota
  4. Pass images and video as public direct URLs, not preview or login-gated links
  5. Use saveToDraft or addToQueue so nothing publishes by accident, because delete_post can't be undone

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

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

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