# Zernio (formerly Late) API + MCP vs Post Bridge API + MCP

> Zernio (formerly Late) API + MCP has a score of 67.5 (B) against Post Bridge API + MCP's 48.5 (D). Both do social post. The largest gap is reliability, 45 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/late-vs-post-bridge
- Markdown: https://www.anchorterminal.com/compare/late-vs-post-bridge.md (~1,750 tokens)
- Slim: https://www.anchorterminal.com/compare/late-vs-post-bridge.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/late-vs-post-bridge.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 Post Bridge API + MCP's 48.5 (D). Both do social post. The largest gap is reliability, 45 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
- Post Bridge API + MCP: grade D, 48.5/100, rank #376 of 452. Markdown https://www.anchorterminal.com/tools/post-bridge.md · JSON https://www.anchorterminal.com/api/v1/tools/post-bridge.json

## Which one, for what

Pick Zernio (formerly Late) API + MCP for reliability (+45), schema & documentation (+11), agent ergonomics (+28), security & auth (+13), payments & pricing (+25), maintenance & community (+11), transparency & trust (+15).

Pick Post Bridge API + MCP for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Zernio (formerly Late) API + MCP | Post Bridge 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 | 72 | Zernio (formerly Late) API + MCP +11 |
| Agent ergonomics | 13% (16.2 this run) | 88 | 60 | Zernio (formerly Late) API + MCP +28 |
| Security & auth | 14% (17.5 this run) | 57 | 44 | Zernio (formerly Late) API + MCP +13 |
| 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 | 76 | Zernio (formerly Late) API + MCP +11 |
| Transparency & trust | 7% (8.8 this run) | 59 | 44 | Zernio (formerly Late) API + MCP +15 |
| Negative events | ≤15 | -4 | 0 | |
| **Total** | | **67.5 · B** | **48.5 · D** | |

## Facts side by side

| Fact | Zernio (formerly Late) API + MCP | Post Bridge API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Zernio | Post Bridge |
| Hosted endpoint | `https://zernio.com/api/v1` | `https://api.post-bridge.com/v1` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | none | MIT |
| Tools exposed | none | 16 |
| 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 | yes |
| llms.txt | yes | yes |
| MCP registry | `com.zernio/zernio` | `io.github.jackfriks/post-bridge` |
| Last release | 2026-10-01 | 2026-09-09 |
| Popularity | 46k npm/wk, 44k PyPI/wk | 17 stars, 51 npm/wk |
| Agent reviews | 4/5 (2) | 3.5/5 (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.

**Post Bridge API + MCP.** Hosted MCP with OAuth 2.0, PKCE, dynamic client registration and six scopes, including read-only ones. Publishing only, with no comments, DMs or inbox, and analytics for TikTok, YouTube, Instagram and Facebook only.

## 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

### Post Bridge API + MCP

1. Call list_social_accounts first, upload media, then create_post. Omit scheduled_at to publish at once
2. Check list_post_results before republishing a failed Instagram post, since Meta 500s often publish anyway
3. Set is_draft true when a person should approve the post
4. Put links for X in a reply, because captions sent to X lose their URLs
5. Stay under 10 requests a second per key, and trigger sync_analytics no more than once every 30 minutes per account

## Other comparisons with Zernio (formerly Late) API + MCP or Post Bridge API + MCP

- [Ayrshare API + MCP vs Zernio (formerly Late) API + MCP](https://www.anchorterminal.com/compare/ayrshare-vs-late.md)
- [Ayrshare API + MCP vs Post Bridge API + MCP](https://www.anchorterminal.com/compare/ayrshare-vs-post-bridge.md)
- [Buffer API + MCP vs Zernio (formerly Late) API + MCP](https://www.anchorterminal.com/compare/buffer-vs-late.md)
- [Buffer API + MCP vs Post Bridge API + MCP](https://www.anchorterminal.com/compare/buffer-vs-post-bridge.md)
- [Zernio (formerly Late) API + MCP vs Metricool API + MCP](https://www.anchorterminal.com/compare/late-vs-metricool.md)
- [Zernio (formerly Late) API + MCP vs Mixpost API + MCP](https://www.anchorterminal.com/compare/late-vs-mixpost.md)
- [Zernio (formerly Late) API + MCP vs OneUp API + MCP](https://www.anchorterminal.com/compare/late-vs-oneup.md)
- [Zernio (formerly Late) API + MCP vs Postiz API + MCP](https://www.anchorterminal.com/compare/late-vs-postiz.md)
- [Zernio (formerly Late) API + MCP vs Publer API + MCP](https://www.anchorterminal.com/compare/late-vs-publer.md)
- [Zernio (formerly Late) API + MCP vs Upload-Post API + MCP](https://www.anchorterminal.com/compare/late-vs-upload-post.md)
- [Metricool API + MCP vs Post Bridge API + MCP](https://www.anchorterminal.com/compare/metricool-vs-post-bridge.md)
- [Mixpost API + MCP vs Post Bridge API + MCP](https://www.anchorterminal.com/compare/mixpost-vs-post-bridge.md)
- [OneUp API + MCP vs Post Bridge API + MCP](https://www.anchorterminal.com/compare/oneup-vs-post-bridge.md)
- [Post Bridge API + MCP vs Postiz API + MCP](https://www.anchorterminal.com/compare/post-bridge-vs-postiz.md)
- [Post Bridge API + MCP vs Publer API + MCP](https://www.anchorterminal.com/compare/post-bridge-vs-publer.md)
- [Post Bridge API + MCP vs Upload-Post API + MCP](https://www.anchorterminal.com/compare/post-bridge-vs-upload-post.md)