# 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. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/late-vs-metricool
- Markdown: https://www.anchorterminal.com/compare/late-vs-metricool.md (~1,700 tokens)
- Slim: https://www.anchorterminal.com/compare/late-vs-metricool.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/late-vs-metricool.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

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 + MCP: grade B, 67.5/100, rank #139 of 452. Markdown https://www.anchorterminal.com/tools/late.md · JSON https://www.anchorterminal.com/api/v1/tools/late.json
- Metricool API + MCP: grade E, 38.7/100, rank #428 of 452. Markdown https://www.anchorterminal.com/tools/metricool.md · JSON https://www.anchorterminal.com/api/v1/tools/metricool.json

## 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

| Category | Weight | Zernio (formerly Late) API + MCP | Metricool API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 35 | Zernio (formerly Late) API + MCP +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 56 | Zernio (formerly Late) API + MCP +27 |
| Agent ergonomics | 13% (16.2 this run) | 88 | 39 | Zernio (formerly Late) API + MCP +49 |
| Security & auth | 14% (17.5 this run) | 57 | 48 | Zernio (formerly Late) API + MCP +9 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Zernio (formerly Late) API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 6 | Zernio (formerly Late) API + MCP +81 |
| Transparency & trust | 7% (8.8 this run) | 59 | 64 | Metricool API + MCP +5 |
| Negative events | ≤15 | -4 | -2 | |
| **Total** | | **67.5 · B** | **38.7 · E** | |

## Facts side by side

| Fact | Zernio (formerly Late) API + MCP | Metricool API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Zernio | Metricool |
| Hosted endpoint | `https://zernio.com/api/v1` | `https://app.metricool.com/api` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | none |
| Tools exposed | none | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `com.zernio/zernio` | not listed |
| Last release | 2026-10-01 | 2025-10-07 |
| Popularity | 46k npm/wk, 44k PyPI/wk | 424 PyPI/wk |
| Agent reviews | 4/5 (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

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