Wire Protocol
| Feature | Status |
|---|
| OP_MSG (commands) | ✅ Supported |
| OP_QUERY (legacy) | ✅ Supported |
| OP_GET_MORE | ✅ Supported |
| OP_KILL_CURSORS | ✅ Supported |
| Checksum flag (0x10000) parse | ✅ Supported |
| Checksum flag (0x10000) write | ❌ Not implemented |
| maxWireVersion | ✅ 21 (MongoDB 8.0+) |
CRUD Operations
| Operation | Status |
|---|
insertOne / insertMany | ✅ Supported |
find with filter, projection, sort, skip, limit | ✅ Supported |
findOne | ✅ Supported |
updateOne / updateMany | ✅ Supported |
deleteOne / deleteMany | ✅ Supported |
findAndModify (update, remove, upsert, returnNew) | ✅ Supported |
count | ✅ Supported |
distinct | ✅ Supported |
getMore (batched cursor) | ✅ Supported |
killCursors | ✅ Supported |
| Bulk writes (document sequences) | ✅ Supported |
Aggregation Pipeline
| Stage | Status |
|---|
$match (pushdown + in-memory) | ✅ Supported |
$sort (multi-field) | ✅ Supported |
$skip | ✅ Supported |
$limit | ✅ Supported |
$project (inclusion/exclusion, _id handling) | ✅ Supported |
$group — $sum, $avg, $min, $max, $first, $last, $push, $addToSet | ✅ Supported |
$count | ✅ Supported |
$unwind (string + document syntax) | ✅ Supported |
$addFields / $set | ✅ Supported |
$sample | ✅ Supported |
$replaceRoot | ✅ Supported |
$sortByCount | ✅ Supported |
$lookup (equality + pipeline syntax) | ✅ Supported |
$out | ✅ Supported |
$facet | ✅ Supported |
| Expression operators ($gt, $gte, $lt, $lte, $eq, $ne, $and, $or, $not, $add, $subtract, $multiply, $divide, $mod, $concat, $cond, $ifNull, $literal, $size) | ✅ Supported |
$bucket, $bucketAuto | ❌ Not implemented |
$graphLookup, $geoNear | ❌ Not implemented |
$merge | ❌ Not implemented |
Index Management
| Operation | Status |
|---|
createIndexes (single, compound, unique) | ✅ Supported |
listIndexes | ✅ Supported |
dropIndexes | ✅ Supported |
| Index-backed queries | ✅ Supported |
| TTL / text / geospatial indexes | ❌ Not implemented |
Authentication & Authorization
| Feature | Status |
|---|
| SCRAM-SHA-256 | ✅ Supported |
| SCRAM-SHA-1 | ✅ Supported |
--no-auth flag | ✅ Supported |
| Client proof verification | ✅ Supported |
| Role-based authorization | ✅ Supported |
Roles: root, readWrite, read | ✅ Supported |
createUser / updateUser / dropUser | ✅ Supported |
usersInfo | ✅ Supported |
| User persistence (SQLite) | ✅ Supported |
Database & Collection Management
| Operation | Status |
|---|
createCollection | ✅ Supported |
drop collection | ✅ Supported |
dropDatabase | ✅ Supported |
listDatabases | ✅ Supported |
listCollections | ✅ Supported |
collStats / dbStats | ✅ Supported |
Tool Compatibility
| Tool | Status |
|---|
| mongosh | ✅ Verified |
| mongodump | ✅ Verified |
| mongorestore | ✅ Verified |
| pymongo 4.x | ⚠️ See note |
| MongoDB drivers (OP_MSG) | ✅ Verified |
⚠️ pymongo 4.17+ C-level BSON encoder strips $-prefixed keys from documents nested inside arrays, which breaks aggregate pipeline stages sent via coll.aggregate(). Use mongosh or raw BSON for aggregate commands. All other operations work correctly with pymongo.