Cid version convert

cid-version-convert · version 1.0.0 · Encoding & checksums · free, no key needed

Convert permitted CIDv0 and CIDv1 envelopes without recomputing their multihash.

Use when you need to: convert cidv0 to cidv1 · convert cidv1 dag-pb to cidv0 · re-encode cid version.

Decide before calling

Read the versioned contract and the supported scope below. Reuse cid-version-convert@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use cid-version-convert@1.0.0 for convert cidv0 to cidv1. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• convert cidv0 to cidv1
• convert cidv1 dag-pb to cidv0
• re-encode cid version
• upgrade legacy cid envelope
• downgrade compatible cid envelope
• preserve cid multihash during conversion

Not supported

• computing a CID from content
• converting non-dag-pb or non-sha2-256 CIDs to CIDv0

Behavior

• Conversion preserves codec and multihash bytes.
• CIDv0 is permitted only for dag-pb with a 32-byte sha2-256 multihash.

Input

• cid (string, required): max length 512
• input_encoding (one of "text", "hex", optional): default "text"
• target_version (one of 0, 1, required)
• output_base (one of "base32", "base58btc", optional): default "base32"

Output

• source_version (integer, required)
• target_version (integer, required)
• cid (string, required)
• bytes_hex (string, required)
• standard (string, required)
• reference (string, required)
• data_version (string, required)

Limits

• max text characters: 512
• max binary bytes: 256

Example

Request input:

{
  "cid": "QmYwAPJzv5CZsnAzt8auVZRnGi2hMrZrm2suKMaqWwaoFY",
  "target_version": 1
}

Response:

{
  "result": {
    "source_version": 0,
    "target_version": 1,
    "cid": "bafybeie5nqv6kd3qnfjuprw2scvucpip3oda2pxyf7hyfasar4zu5flr5m",
    "bytes_hex": "017012209d6c2be50f70695347c6da90ab413d0fdb860d3ef82fcf8282408f334e9571eb",
    "standard": "Multiformats CID Specification 1.0",
    "reference": "CID specification 1.0 §CIDv0/§CIDv1 and multicodec/multihash/multibase tables",
    "data_version": "multiformats tables snapshot 2026-10-24"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "cid-version-convert",
  "version": "1.0.0",
  "input": {
    "cid": "QmYwAPJzv5CZsnAzt8auVZRnGi2hMrZrm2suKMaqWwaoFY",
    "target_version": 1
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/cid-version-convert/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"cid":"QmYwAPJzv5CZsnAzt8auVZRnGi2hMrZrm2suKMaqWwaoFY","target_version":1}'

The machine-readable contract is at /v1/tools/cid-version-convert/versions/1.0.0.

CLI

node cli.mjs run cid-version-convert 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Cid parse: Parse a CIDv0 or CIDv1 envelope without hashing content.
• Segwit address encode: Encode a witness program as a native segwit address using Bech32 for v0 and Bech32m for v1-v16.
• Bech32 convert bits: Regroup integers between bit widths using BIP 173 rules, rejecting bad leftover padding.
• Bech32 encode: Encode lowercase HRP and 5-bit data as Bech32 or Bech32m text using that checksum.
• Pem envelope format: Format a label and lowercase hex bytes as a canonical RFC 7468 PEM envelope.
• Pem envelope parse: Parse one RFC 7468 textual envelope into its label and lowercase hex bytes.