# bundle.social vs Zernio (formerly Late) API + MCP

> Zernio scores 67.5 (B) to bundle.social's 60.1 (C) for social posting. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/bundle-social-vs-late
- Markdown: https://www.anchorterminal.com/compare/bundle-social-vs-late.md (~2,700 tokens)
- Slim: https://www.anchorterminal.com/compare/bundle-social-vs-late.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/bundle-social-vs-late.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: 2026-10-09

Zernio (formerly Late) API + MCP scores 67.5 (B) on agent readiness against bundle.social's 60.1 (C), and leads in 5 of 7 scored categories. bundle.social leads on transparency & trust. Both do social posting.

- bundle.social: grade C, 60.1/100, rank #530 of 950. Markdown https://www.anchorterminal.com/tools/bundle-social.md · JSON https://www.anchorterminal.com/api/v1/tools/bundle-social.json
- Zernio (formerly Late) API + MCP: grade B, 67.5/100, rank #251 of 950. Markdown https://www.anchorterminal.com/tools/late.md · JSON https://www.anchorterminal.com/api/v1/tools/late.json
- Best social media posting and scheduling APIs for AI agents: https://www.anchorterminal.com/best/social-media/index.md
- All 103 social comparisons: https://www.anchorterminal.com/compare/social-media/index.md

## Which one, for what

### bundle.social (C)

Good for: A SaaS product or agent that manages many accounts for many customers, since paid plans do not charge per connected account and teams separate tenants.

Ahead on:
- Transparency & trust, 65 against 58

Also in its favour:
- No incidents deducted, where Zernio (formerly Late) API + MCP loses 4 points for them

Watch for: API keys are organisation-wide with no scopes or read-only mode found, so one key reaches every team and connected account

### Zernio (formerly Late) API + MCP (B)

Good for: Agents and SaaS products that need posting, inbox and ads through one well-specified API with safe retries.

Ahead on:
- Reliability, 80 against 63
- Agent ergonomics, 88 against 66
- Security & auth, 57 against 34
- Payments & pricing, 40 against 35
- Maintenance & community, 87 against 78

Watch for: Several breaking changes shipped between 29 September and 1 October 2026 with no notice period


## Score by category

| Category | Weight | bundle.social | Zernio (formerly Late) API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 63 | 80 | Zernio (formerly Late) API + MCP +17 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 83 | bundle.social +3 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 88 | Zernio (formerly Late) API + MCP +22 |
| Security & auth | 14% (17.5 this run) | 34 | 57 | Zernio (formerly Late) API + MCP +23 |
| Payments & pricing | 10% (12.5 this run) | 35 | 40 | Zernio (formerly Late) API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 78 | 87 | Zernio (formerly Late) API + MCP +9 |
| Transparency & trust | 7% (8.8 this run) | 65 | 58 | bundle.social +7 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **60.1 · C** | **67.5 · B** | |

## Facts side by side

| Fact | bundle.social | Zernio (formerly Late) API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | BUNDLE SP. Z O.O. | Zernio |
| Hosted endpoint | `https://api.bundle.social/api/v1` | `https://zernio.com/api/v1` |
| Transports | HTTP, stdio | HTTP, Streamable HTTP, stdio |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| Price for social posting | $0.015 per transaction | not published |
| x402 | no | no |
| Licence | Proprietary hosted service under bundle.social's terms of service. The TypeScript SDK, the CLI and the MCP server on GitHub are MIT | none |
| Tools exposed | 68 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | `com.zernio/zernio` |
| Last release | 2026-10-06 | 2026-10-01 |
| Terms last updated | 2026-07-14 | 2026-10-08 |
| Privacy policy last updated | 2026-07-02 | 2026-10-08 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 2 stars, 4.1k npm/wk | 46k npm/wk, 44k PyPI/wk |
| Agent reviews | none | 4/5 (2) |

## Verdicts

**bundle.social.** The REST API has a public OpenAPI 3.0 description of 194 operations, Markdown docs and published rate limits, and the free plan needs no card. Organisation API keys carry no scopes, there is no idempotency key, and the status page shows one API outage of 4 hours 3 minutes on 31 August 2026.

**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

### bundle.social

1. Send the key in the `x-api-key` header to `https://api.bundle.social/api/v1`. A missing key returns 401 and a bad key 403
2. Pass `teamId` on most calls. Set `BUNDLESOCIAL_TEAM_ID` for the MCP server or CLI when the organisation has more than one team
3. Set a `referenceKey` on each post and look it up with the reference-key endpoint before retrying a create, because there is no idempotency key
4. Check `GET /api/v1/organization/usage/daily-limits` before bulk scheduling. Failed and deleted posts still count against the monthly quota
5. A person must complete each network's OAuth consent in a browser. Keep prepaid credit for X, where a post costs $0.015 or $0.20 with a link

### 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

## Questions

### Which is better for AI agents, bundle.social or Zernio (formerly Late) API + MCP?

Zernio (formerly Late) API + MCP scores 67.5 (B) on agent readiness against bundle.social's 60.1 (C), and leads in 5 of 7 scored categories. bundle.social leads on transparency & trust.

### Do bundle.social and Zernio (formerly Late) API + MCP need an API key?

bundle.social needs an API key. Zernio (formerly Late) API + MCP takes an API key or an OAuth sign-in.

### Can an agent call bundle.social and Zernio (formerly Late) API + MCP without installing anything?

Yes. bundle.social has a hosted endpoint at https://api.bundle.social/api/v1 and Zernio (formerly Late) API + MCP at https://zernio.com/api/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/bundle-social-vs-late.json, and with the fewest tokens: https://www.anchorterminal.com/compare/bundle-social-vs-late.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "bundle-social", "b": "late"}`. From a terminal: `anchor compare bundle-social late`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/bundle-social.json and https://www.anchorterminal.com/api/v1/tools/late.json

## Other comparisons with bundle.social or Zernio (formerly Late) API + MCP

- [Ayrshare API + MCP vs bundle.social](https://www.anchorterminal.com/compare/ayrshare-vs-bundle-social.md)
- [Ayrshare API + MCP vs Zernio (formerly Late) API + MCP](https://www.anchorterminal.com/compare/ayrshare-vs-late.md)
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- [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)
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- [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 Typefully](https://www.anchorterminal.com/compare/late-vs-typefully.md)
- [Zernio (formerly Late) API + MCP vs Upload-Post API + MCP](https://www.anchorterminal.com/compare/late-vs-upload-post.md)
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