# Zernio (formerly Late) API + MCP vs Publer API + MCP

> Zernio (formerly Late) API + MCP has a score of 67.5 (B) against Publer API + MCP's 47.1 (D). Both do social post. The largest gap is maintenance & community, 46 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/late-vs-publer
- Markdown: https://www.anchorterminal.com/compare/late-vs-publer.md (~1,650 tokens)
- Slim: https://www.anchorterminal.com/compare/late-vs-publer.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/late-vs-publer.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 Publer API + MCP's 47.1 (D). Both do social post. The largest gap is maintenance & community, 46 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
- Publer API + MCP: grade D, 47.1/100, rank #388 of 452. Markdown https://www.anchorterminal.com/tools/publer.md · JSON https://www.anchorterminal.com/api/v1/tools/publer.json

## Which one, for what

Pick Zernio (formerly Late) API + MCP for reliability (+20), schema & documentation (+37), agent ergonomics (+33), security & auth (+16), payments & pricing (+25), maintenance & community (+46).

Pick Publer API + MCP for transparency & trust (+10).

## Score by category

| Category | Weight | Zernio (formerly Late) API + MCP | Publer API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 60 | Zernio (formerly Late) API + MCP +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 46 | Zernio (formerly Late) API + MCP +37 |
| Agent ergonomics | 13% (16.2 this run) | 88 | 55 | Zernio (formerly Late) API + MCP +33 |
| Security & auth | 14% (17.5 this run) | 57 | 41 | Zernio (formerly Late) API + MCP +16 |
| Payments & pricing | 10% (12.5 this run) | 40 | 15 | Zernio (formerly Late) API + MCP +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 41 | Zernio (formerly Late) API + MCP +46 |
| Transparency & trust | 7% (8.8 this run) | 59 | 69 | Publer API + MCP +10 |
| Negative events | ≤15 | -4 | 0 | |
| **Total** | | **67.5 · B** | **47.1 · D** | |

## Facts side by side

| Fact | Zernio (formerly Late) API + MCP | Publer API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Zernio | Publer |
| Hosted endpoint | `https://zernio.com/api/v1` | `https://app.publer.com/api/v1` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Paid |
| 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 | none |
| Popularity | 46k npm/wk, 44k PyPI/wk | none |
| Agent reviews | 4/5 (2) | 3/5 (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.

**Publer API + MCP.** Scoped API keys (workspaces, accounts, posts, media, analytics) with 401 and 403 errors that name the missing scope or header. API and MCP only on Business and Enterprise, and the free plan has no API.

## 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

### Publer API + MCP

1. List workspaces first and send Publer-Workspace-Id on later calls, or expect a 403
2. Poll /job_status/{job_id} after posts/schedule and read payload.failures, since status reads complete even when posts failed
3. Use the Bearer-API scheme, not Bearer
4. Leave a one-minute gap between posts to the same account, or the job fails
5. Read X-RateLimit-Reset after a 429 and wait until then, as there's no Retry-After

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