Item Metadata API (MDAPI) as free key-value/JSON store
- Free allowance
- No per-item metadata size is published; unlimited items x one JSON doc each, transaction-safe, free.
- Verdict
- fails: quotathe free allowance is too small to matter
- Cost
- free tier
- Identity
- email?placeholder, not evidence; card unknown, phone unknown
- Binding limit
- request-rateunverified: writes are tasks limited per user over a period, HTTP 429 Too Many Requests at the threshold; the threshold is not published
- Evidence
- reported9 sources; a third party said so
- Freshness
- stale on 2026-11-19checked 2026-11-04 (live); stale on 2026-11-19
| Free tier | No per-item metadata size is published; unlimited items x one JSON doc each, transaction-safe, free. unit unlimited; metered on unstated |
|---|---|
| Price | none stated |
| Limits |
One item per call, no wildcarding; custom fields must follow XML naming; writes are queued like any other item transaction; not intended for bulk blob data. |
| Binding | request-rate writes are tasks limited per user over a period (HTTP 429); the threshold is not published |
| Identity | email (placeholder) Internet Archive account (email address, screen name, password); the S3 keys used for MDAPI writes come from that account. |
| Egress | Free reads (public items), gzip/deflate supported |
| Per-object cap | not stated |
| Retention | not stated |
| Interface | rest rest |
| Tooling | ia metadata -m / Python MDAPI; auth via the same IAS3 keys (Authorization: LOW) |
| Composes with | Side-car index for the 20TiB: one small JSON doc per item holding checksums, shard maps, source URLs — solves IAS3's 'cannot list all my items' problem without running your own database. |
| Reliability | Safe for bookkeeping, useless for bytes; concurrent writers need the documented concurrency pattern or they clobber metadata. |
| Evidence note | reported reported: vendor pages read on 2026-11-03 show the sign-up fields (https://archive.org/account/signup), the per-user write task limit (https://archive.org/developers/md-write.html) and the one-item-per-call rule (https://archive.org/developers/metadata.html). The free allowance and the write threshold are not stated there; retention and per-object cap were not read. |
| Parsed numbers |
|
Evidence 9
| date | source | what it proved |
|---|---|---|
| 2026-10-21 | archive.org/developers/metadata.html | (snapshot 2026-02-04) — 'may even store ad hoc JSON data in a transaction-safe manner', 'MDAPI cannot operate on more than one item at a time. There is no wildcarding' |
| 2026-10-21 | archive.org/developers/ias3.html | S3 keys sent with 'Authorization: LOW' are accepted by MDAPI write |
| 2026-11-03 | archive.org/account/signup | the Internet Archive sign-up asks for an email address, a screen name and a password |
| 2026-11-03 | archive.org/developers/md-write.html | metadata writes are rate limited per user; the threshold is not given |
| 2026-11-03 | archive.org/developers/metadata.html | part of the text of Limits, above |
| 2026-11-03 | archive.org/developers/metadata.html | S3 keys authorize MDAPI calls with Authorization: LOW |
| 2026-11-04 | archive.org/developers/md-write.html | metadata writes are rate limited per user; the threshold is not given |
| 2026-11-04 | archive.org/developers/metadata.html | part of the text of Limits, above |
| 2026-11-04 | archive.org/account/signup | the sign-up asks for an email address |
More fields 1
| dead end | {"failure_class": "quota","why": "No per-item metadata size is published; unlimited items x one JSON doc each, transaction-safe, free.","retry_when": null,"first_recorded": "2026-10-21"} |
|---|
Unknown values 4
- per object cap notes: the field may be stated in a source that was not read
- per object cap stated: the field may be stated in a source that was not read
- retention notes: the field may be stated in a source that was not read
- retention stated: the field may be stated in a source that was not read