Spanly
MCP server observability: traces, security scans, and auto-fix patches
If you run MCP servers in production, this is the tool to fill the gap your APM leaves open. It captures protocol-level detail, scans for security issues, and patches live traffic without code changes. Just don't treat it as a replacement for Datadog or Sentry—it's a complement, and it shows.
Verified 3d ago · liveness 74/100 · cite: rightaichoice.com/tools/spanly
- Engineering teams running MCP servers in production who need protocol-level visibility
- B2B SaaS companies embedding MCP tool calling into their products
- Platform teams needing MCP-native observability without code changes
- Developers already using APMs like Datadog or Sentry who want deeper MCP insight
- Organizations not using MCP or AI agents
- Teams needing full-stack APM coverage (Spanly is MCP-specific)
- Heavy users requiring >75M MCP packets/month without an enterprise contract
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- Real pros & cons from real users
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Skip Spanly if you don't run MCP servers or AI agents, if you need a full-stack APM (it's MCP-specific), or if you're above 75M packets/month without an enterprise contract.
Past the 50,000 free packets, usage is metered per packet on a graduated ladder — $5.00 per 100k up to 2.5M, $4.50 up to 10M, $4.00 up to 25M, $3.50 up to 75M — so high-traffic servers can rack up significant monthly
Spanly's packet-based pricing scales with actual usage, starting with a free 50,000 packets on every plan. Pro at $82.50/mo is competitive for a specialized MCP-observability tool, though cheaper than a full APM like Datadog. Business at $415.83/mo adds SSO and audit log, making it cost-effective for teams needing compliance. Founding Partner Program offers 50% off usage pricing for the first ten production teams.
In short
Spanly — MCP server observability: traces, security scans, and auto-fix patches. Best for Engineering teams running MCP servers in production who need protocol-level visibility, B2B SaaS companies embedding MCP tool calling into their products, Platform teams needing MCP-native observability without code changes. Free to start; paid plans from $82.5099/mo.
What's new in Spanly
Checked 8 days agoAcross the latest 4 updates: 1 launch and 3 news mentions.
Agentjacking: when your telemetry becomes a prompt-injection vector
Researchers demonstrated RCE via public Sentry DSN by hiding shell commands in error reports; Spanly's MCP observability surfaces the read-to-exec pivot.
MCP OpenTelemetry tracing vs Spanly: what each one actually captures
MCP Python SDK now ships OpenTelemetry tracing per SEP-414; Spanly provides packet-level MCP observability complementing OTel spans.
EU AI Act traceability for MCP tool calls
Practical checklist for logging and traceability of MCP tool calls under EU AI Act compliance requirements.
Introducing Spanly: observability built for MCP
Spanly launched as observability for MCP servers: two-minute install, MCP-native telemetry, EU and US data residency.
What people actually say about Spanly — is it worth it?
We ran a structured research pass across product reviews, community discussions, and post-purchase forum threads to surface the patterns vendors won't publish themselves. Below: the recurring strengths, the hidden costs people mention most, and the cohort that consistently regrets adopting this tool.
25 mentions across 4 sources (Hacker News, YouTube, Product Hunt, Bluesky) · researched Jul 23, 2026.
- +MCP-native observability fills a real gap that APMs miss.
- +Installs in under 5 minutes with no code changes.
- +Captures full JSON-RPC payloads (tool calls, prompts, resources).
- +Per-tool performance metrics (P50/P95/P99) are actionable.
- +Open-source SDK and CLI under Apache 2.0 license.
- −Very limited community feedback — risky for production decisions.
- −No independent reviews or case studies available yet.
- −Solo-founder project raises continuity concerns for enterprises.
- −Pricing for high-volume MCP calls could become expensive.
- −Only useful if you run MCP servers — zero generalizability.
- • Overages for additional servers or data volume not clearly disclosed
- • PagerDuty integration requires Pro plan or higher
Viability Score
How well maintained and how widely used is Spanly? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: September 2026
How we score →Key Features
- Real-time MCP request tracing with full JSON-RPC payload capture
- Per-server, per-client, per-tool performance metrics (P50/P95/P99)
- Security scanners for prompt injection, tool poisoning, secrets, and schema issues
- Automated patch workflow: canary, A/B test, then apply fixes to live traffic
- Health monitors that check server uptime and alert on downtime
- Error tracking with stack traces and AI-generated fault write-ups
- Drift detection that identifies degraded tools over time
- Client conformance monitoring (Claude Code, Cursor, Codex, etc.)
- Data residency in US and EU regions, selectable per project
- OpenTelemetry ingestion and export for MCP spans
- Public dashboards with read-only share links
- Alert rules with Slack, email, webhook, and in-app notifications
- MCP Gateway on your own domain (Business)
- SAML/OIDC single sign-on (Business)
- Audit log (Business)
About Spanly
Spanly is an observability platform built specifically for Model Context Protocol (MCP) servers. It captures every JSON-RPC message—tool calls, prompts, and resource reads—along with full request/response payloads, durations, and errors. That means engineering teams running MCP servers in production get protocol-level visibility that general-purpose APMs like Datadog, Sentry, and New Relic simply don't offer. Spanly installs in about two minutes with a one-line SDK or a CLI wrapper, and it works with your existing stack—it ingests OpenTelemetry-formatted MCP spans and can export traces back to your APM, so you don't have to rip anything out. Spanly positions itself as an additive layer on top of your current APM, not a replacement. Its dashboards break down usage by tool, prompt, resource, client, and server, with per-client conformance tracking that shows how Claude Code, Cursor, Codex CLI, Windsurf, Copilot, and Zed use your MCP server differently. Health monitors check server uptime on a schedule and alert your channels on downtime. Security scanners screen live traffic for prompt injection, tool poisoning, secrets in arguments, and schema issues, then rank findings by severity. When a problem is found, Spanly can draft a patch, test it on a slice of live sessions (canary and A/B modes), and apply it to all traffic until you ship the fix upstream. Pricing is packet-based: every JSON-RPC message—request, response, or notification—counts as one packet, and every plan includes 50,000 free packets per month. The Free tier ($0, no credit card) samples at 10% past the allowance and includes 30-day retention and one health monitor. Pro ($82.50/mo billed annually) adds 90-day retention, five health monitors, public dashboards, and notifications. Business ($415.83/mo billed annually) includes 12-month retention, 100 health monitors, SSO, audit log, and MCP Gateway on your own domain. Enterprise pricing kicks in above 75M packets/month. Data residency is selectable per project (US or EU).
Behind the Verdict
Spanly fills a real gap in the observability stack for teams running MCP servers in production. General-purpose APMs like Datadog, Sentry, and New Relic see HTTP requests and stack traces, but they don't see the MCP protocol itself—the tool calls, prompts, and resource reads that define how AI agents interact with your server. Spanly captures every JSON-RPC packet with full payloads, so you can debug exactly why a tool call failed, which client sent malformed arguments, or why a particular prompt is slow. The per-client conformance tracking is a standout feature: it shows how Claude Code, Cursor, Codex CLI, Windsurf, Copilot, and Zed each use your server differently, which is critical because clients often skip tools or pass incompatible arguments. The security scanning is another differentiator—it screens live traffic for prompt injection, tool poisoning, secrets in arguments, and schema issues, then ranks findings by severity. The automated patch workflow takes it further: Spanly can draft a fix, test it on a small slice of live sessions (canary or A/B), and apply it to all traffic until you ship the fix upstream. That's a powerful capability for teams that need to respond quickly to security issues without code changes. The packet-based pricing is transparent and predictable: you pay per JSON-RPC message, not per server or seat, and every plan includes a 50,000-packet free allowance. The graduated ladder ($5.00 per 100k up to 2.5M, then decreasing) means costs scale with usage, and you can set a monthly spend cap. The free tier is generous for evaluation, and the paid tiers add longer retention, more health monitors, public dashboards, and notifications. For teams needing compliance, Business adds SSO (SAML/OIDC), audit log, and EU/US data residency—important for EU AI Act traceability. Where Spanly doesn't fit: if you're not using MCP or AI agents, this tool is irrelevant. It's not a full-stack APM—it's specifically for MCP servers, so you still need your existing APM for HTTP and infrastructure monitoring. Also, if you're at extremely high volume (above 75M packets/month), you'll need an Enterprise contract, which is custom. Overall, Spanly is a must-have for teams running MCP servers in production that want protocol-level visibility and security scanning—just keep your existing APM for broader coverage.
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Real-world workflow fit
Concrete scenarios for the personas Spanly actually fits — and what changes day-one when you adopt it.
Immediately after installing the CLI wrapper on your server, you view the Requests view in the dashboard to see every tool call, prompt, and resource read with durations and errors. You spot a slow tool (code_exec at 982ms) and inspect its JSON-RPC payload to identify the bottleneck.
Outcome: You pinpoint the issue without digging through HTTP logs, and you share a read-only dashboard link with your team to track performance trends.
You set up health monitors on three MCP servers (Prod US, EU edge, staging) and configure alerts to Slack. When staging goes down, you're notified immediately, and you see uptime history to confirm it's a recurring issue.
Outcome: You reduce downtime response time from hours to minutes, and you have the data to plan infrastructure changes.
You enable daily security scans on your MCP server. Within a day, the dashboard flags a critical prompt injection issue in tool output, and you use the automated patch workflow to test a fix on a 20% canary slice before applying to all traffic.
Outcome: You quickly mitigate a security risk without manual patching, and you can push the fix upstream with confidence.
Use Cases
- Monitor MCP server performance with real-time traces and P50/P95/P99 latency
- Debug tool call errors by inspecting full JSON-RPC payloads and stack traces
- Track session durations and per-client request volumes across deployments
- Set up alerts for error rate spikes, slow tools, or resource access failures
- Correlate MCP traces with existing APM traces via W3C trace context
- Audit all actions with SSO and audit log for compliance (EU AI Act, SOC2)
Limitations
- Spanly is an MCP server observability platform, not an AI model provider, so it has no underlying AI model.
- The Free plan includes 50,000 free packets per month with a soft cap; additional packets are sampled.
- Pro ($82.50/month billed annually) and Business ($415.83/month billed annually) plans include 50,000 free packets per month then $5.00 per 100k packets, decreasing with volume.
- Enterprise pricing kicks in above 75M packets/month with a custom per-packet rate below $3.50 per 100k.
- Overage beyond included packets is metered monthly.
as of 2026-08-25
Verification history
We have re-verified Spanly 8 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — re-checked, vendor evidence unchanged
- — re-checked, vendor evidence unchanged
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
Showing the 6 most recent of 8 verification passes.
Free to cite with attribution — this page re-verifies continuously.
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Plans compared
For each published Spanly tier: who it actually fits, and what it adds vs. the previous tier. Cross-reference the cost calculator above for projected annual outlay.
Free
$0/mo
Ideal for
Solo developers or small teams evaluating Spanly on a single MCP server, with up to 50k packets/month and 30-day retention.
What this tier adds
Starting tier: 50k free packets, sampled ingestion past allowance, 30-day retention, 2 seats, daily security scans, 1 health monitor.
Pro
$82.50/mo (billed annually at $990)
Ideal for
Teams running MCP servers in production needing deeper insights, longer retention (90 days), and proactive alerts.
What this tier adds
Adds 90-day retention, unlimited seats, security scans every 30 min, 5 health monitors, public dashboards, and Slack/email/webhook notifications.
Business
$415.83/mo (billed annually at $4,990)
Ideal for
Organizations with multiple MCP servers needing full visibility, compliance features (SSO, audit log), and custom domains.
What this tier adds
Adds 12-month retention, MCP Gateway on your domain, 100 health monitors, SAML/OIDC SSO, audit log, and priority support.
Enterprise
Custom
Ideal for
High-volume teams (above 75M packets/month) needing custom pricing, retention, and dedicated support.
What this tier adds
Custom per-packet rate below $3.50/100k, dedicated support, custom retention, and SLA guarantees.
Where the pricing makes sense
The company stage and team size where Spanly's pricing actually pencils out — and where peers do it cheaper.
Spanly's packet-based pricing scales with actual usage, starting with a free 50,000 packets on every plan. Pro at $82.50/mo is competitive for a specialized MCP-observability tool, though cheaper than a full APM like Datadog. Business at $415.83/mo adds SSO and audit log, making it cost-effective for teams needing compliance. Founding Partner Program offers 50% off usage pricing for the first ten production teams.
Setup time & first value
How long it actually takes to get something useful out of Spanly — broken out by persona, not the marketing-page minute.
For a single MCP server, you'll have live traces in under 5 minutes: create a project, copy your API key, and run the one-line CLI installer (curl -fsSL https://spanly.com/setup.sh | sh). If you prefer SDKs, the TypeScript or Python middleware adds one line to your server code. No code changes needed with the CLI.
Switching to or from Spanly
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
- →From Datadog/Sentry/New Relic: Spanly complements these—keep them for HTTP/infra, add Spanly for MCP-specific traces via OTel export, so no migration needed, just additive setup.
- ↗To another MCP observability tool: export your traces via OpenTelemetry to any OTel-compatible backend, so you can switch without losing data.
Integrations
Resources & Guides
- Documentationspanly.com
Docs · Spanly
Full product docs from spanly.com
- Documentationspanly.com
Python Sdk · Spanly
Full product docs from spanly.com
- API Referencespanly.com
Cli · Spanly
Methods, params, types from spanly.com
- Documentationspanly.com
Gateway · Spanly
Full product docs from spanly.com
- Resourcespanly.com
Blog · Spanly
Helpful link from spanly.com
Tutorials & Learning
Official links
Tools that pair well with Spanly
Common stack mates teams adopt alongside Spanly, with the specific reason each pairing earns its keep.
Featured Head-to-Head Comparisons
Spanly vs Spider Cloud
Choose Spanly if you need dedicated observability for MCP servers in production—its real-time tracing, payload capture, and integrated alerting fill a gap APMs can't cover. Choose Spider Cloud if your AI agent requires fast, cost-effective web data extraction with structured output; its pay-as-you-go model and Rust engine make it ideal for high-volume scraping. Both are complementary, not directly competitive.
Spanly vs Temporal Ai
Choose Spanly if you already have an APM and need deep MCP-specific tracing with low overhead; it's purpose-built for MCP servers. Choose Temporal if you need to build reliable, long-running AI agent workflows with automatic retries and state persistence, even without MCP. For teams doing both, they complement each other.
Spanly vs Voyage Ai
For teams running MCP servers in production, Spanly is the clear choice with MCP-native observability, open-source SDK, and transparent freemium pricing. Voyage AI excels in enterprise RAG retrieval with domain-specific embeddings and rerankers, but lacks pricing transparency and pre-built integrations. Choose Spanly for monitoring MCP server health, Voyage for improving search accuracy over specialized documents.
Alternatives to Spanly
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